Opinion of the Court by

The plaintiff-appellant Hawaii Home Infusion Associates (HHIA) appeals from the first circuit court’s March 28, 2005 judgment, the Honorable Karen S.S. Ahn presiding,1 awarding summary judgment in favor of the defendants-appellees Nelson B. Befitel, director of the State of Hawaii’s Department of Labor and Industrial Relations (DLIR) [hereinafter, “the director”], Kuhio Motors, Inc. (KM), Adjusting Services of Hawaii, Inc. (ASH), and Majestic Insurance Company (MIC) [hereinafter, collectively, “the Appel-lees”] and against HHIA and dismissing “[a]ll other claims and all other parties.”

On appeal, HHIA challenges the circuit court’s judgment insofar as it effectively barred its appeal from the director’s decision to the Labor and Industrial Relations Appeals Board.

For the reasons discussed infra in section III.B, we hold that the first circuit court lacked subject matter jurisdiction over HHIA’s declaratory action and, accordingly, vacate the judgment below and remand with instructions to dismiss HHIA’s complaint.

I. BACKGROUND

On April 2, 2004, HHIA filed a “petition”2 for declaratory relief in the first circuit court, inter alia, challenging, on “substantive due process” and separation-of-powers grounds, the provision of Hawai'i Administrative Rules (HAR) § 12-15-94(d) (2001) that bars appeals from certain billing-dispute resolution decisions.3 As bases for *89the first circuit court’s jurisdiction, HHIA invoked Hawai'i Revised Statutes (HRS) §§ 91-7 (1993)4 and 632-1 (1993) (concerning, inter alia, circuit courts’ jurisdiction over declaratory actions). According to its complaint, HHIA’s “principal offices” are located in Lhu'e, in Kaua'i County, which is coextensive with the fifth judicial circuit, see HRS § 603-1(4) (Supp. 1994). HHIA “renders medical care, medical services, and medical supplies ... to home-bound patients on the island of Kaua[’]i” and, in particular, prepared and monitored the delivery of a “specially formulated” medicinal compound to a worker’s compensation claimant, the defendant Edward Shepherd. A billing dispute among HHIA, ASH, and MIC ensued, and the director “ordered the parties” into the billing dispute process described in HAR § 12-15-94(d). HHIA asserted that the director’s resulting decision was adverse to it and that HAR § 12-15-94(d) unconstitutionally deprived it of the right to an appeal therefrom.

On June 21, 2004, the director moved to dismiss HHIA’s complaint on the grounds that it “was filed in the wrong circuit.”5 (Quoting HRS § 91-7(a).) (Citing HRS § 603-37.5 (concerning “[cjure or waiver of [venue] defects”); Hawai'i Rules of Civil Procedure (HRCP) Rules 7 (concerning “form of motions”) and 12.6) See also KM’s, ASH’s, and MIC’s Answer at 4 (“[HHIAJ’s claims are barred ... because of ... lack of jurisdiction.”). HHIA responded that the director’s motion amounted to a challenge of venue rather than subject matter jurisdiction and was therefore untimely inasmuch as the director did not object to venue in his answer or in a pre-answer motion. (Quoting HRCP Rule 12(b) and (h), see supra note 5.) HHIA argued in the alternative that, were the director to claim that his motion asserted a challenge of jurisdiction rather than venue, he would be mistaken inasmuch as “venue is generally not a jurisdictional factor in Ha-wai[’]i.”7 (Citing Life of the Land v. Land Use Comm’n, 58 Haw. 292, 294-95, 298, 568 P.2d 1189, 1191-94 (1977).) Construing its *90argument generously, HHIA seems to have asserted that, rather than creating a territorial limitation on subject matter jurisdiction, HRS § 91-7(a) augments HRS § 603-36(5) (1993),8 granting the plaintiff the option to litigate in the plaintiffs own domicile notwithstanding the general venue rule to the contrary.9

The director’s July 2, 2004 reply countered “that HRS § 91-7 pertains to jurisdiction and is not a matter of venue.” He cited this court’s observation, in Life of the Land, that “[t]he circuit court ... has jurisdiction to render declaratory judgments under HRS § [ ] 91-7,” 58 Haw. at 295, 568 P.2d at 1192 (emphasis added).10 The director further implied that, inasmuch as HRS § 91-7 is distinct from HRS ch. 603, pt. IV (1993) and § 604-7 (Supp. 2002), concerning venue in the circuit and district courts, respectively, “it should not be assumed that [HRS] § 91-7 contains a ‘venue’ provision.” Finally, the director seems to have argued that a geographic reference in the statute under scrutiny “does not automatically” preclude its construction as a limitation on jurisdiction. (Quoting Hawaiian Tel. Co. v. Agsalud, 67 Haw. 39, 40, 675 P.2d 777, 778 (1984).)

On July 9, 2004, the circuit court conducted a hearing on the director’s motion to dismiss, the transcript of which is not in the record, cf. Hawaii Rule of Appellate Procedure 10(a) (“The record on appeal shall consist of ...: ... (4) the transcripts prepared for the record on appeal ....”) (emphasis added). In its July 21, 2004 order, the circuit court denied the director’s motion. The circuit comí proceeded to the merits and, on January 3, 2005, granted the director’s December 2, 2004 motion for summary judgment, and denied HHIA’s October 1, 2004 motion for summary judgment. Accordingly, on March 28, 2005, after disposing of HHIA’s motion for reconsideration, the circuit court entered final judgment in favor of the Appel-lees and against HHIA and dismissed all other claims and parties. On April 26, 2005, HHIA filed its notice of appeal.

II. STANDARDS OF REVIEW

A. Subject Matter Jurisdiction

Inasmuch as we are guided by the principle that, “[i]f a court lacks jurisdiction over the subject matter of a proceeding, any judgment rendered in that proceeding is invalid [and that,] therefore, *91such a question is valid at any stage of the ease, ... [we ... are] obliged to first [e]nsure that [the circuit court] ha[d subject matter] jurisdietion.[”]

Tamashiro v. Dep’t of Human Servs., 112 Hawai'i 388, 398-99, 146 P.3d 103, 113-14 (2006) (some brackets in original and some added) (quoting Bush v. Hawaiian Homes Comm’n, 76 Hawai'i 128, 133, 870 P.2d 1272, 1277 (1994)).

B. Statutory Interpretation

[“] The interpretation of a statute is a question of law reviewable de wo.[”] State v. Arceo, 84 Hawai'i 1, 10, 928 P.2d 843, 852 (1996)[ (internal quotation signals omitted) ].

Furthermore, our statutory construction is guided by established rules:

When construing a statute, our foremost obligation is to ascertain and give effect to the intention of the legislature, which is to be obtained primarily from the language contained in the statute itself. And we must read statutory language in the context of the entire statute and construe it in a manner consistent with its purpose.

When there is doubt, doubleness of meaning, or indistinctiveness or uncertainty of an expression used in a statute, an ambiguity exists....

In construing an ambiguous statute, “[t]he meaning of the ambiguous words may be sought by examining the context, with which the ambiguous words, phrases, and sentences may be compared, in order to ascertain their true meaning.” HRS § 1-15(1) [ (1993) ]. Moreover, the courts may resort to extrinsic aids in determining legislative intent. One avenue is the use of legislative history as an interpretive tool.

Gray [v. Admin. Dir. of the Court], 84 Hawai'i [138,] 148, 931 P.2d [580,] 590 [ (1997) ] (quoting State v. Toyomura, 80 Hawai'i 8, 18-19, 904 P.2d 893, 903-04 (1995)) (brackets and ellipsis points in original) (footnote omitted). This court may also consider “[t]he reason and spirit of the law, and the cause which induced the legislature to enact it ... to discover its true meaning.” HRS § 1-15(2).... “Laws in pari materia, or upon the same subject matter, shall be construed with reference to each other. What is clear in one statute may be called upon in aid to explain what is doubtful in another.” HRS § 1-16 (1993).

State v. Koch, 107 Hawai'i 215, 220, 112 P.3d 69, 74 (2005) [ (some brackets added and some in original) (one ellipsis added and some in original)] (quoting State v. Kaua, 102 Hawai'i 1, 7-8, 72 P.3d 473, 479-480 (2003)). Absent an absurd or unjust result, see State v. Haugen, 104 Hawai'i 71, 77, 85 P.3d 178, 184 (2004), this court is bound to give effect to the plain meaning of unambiguous statutory language; we may only resort to the use of legislative history when interpreting an ambiguous statute. State v. Valdivia, 95 Hawai'i 465, 472, 24 P.3d 661, 668 (2001).

Courbat v. Dahana Ranch, Inc., 111 Hawai'i 254, 260-61, 141 P.3d 427, 433-34 (2006) (emphasis omitted) (some brackets and ellipses added and some in original).

III. DISCUSSION

A. Introduction

The dispositive issue before us is whether HRS § 91-7(a), see supra note 3—under which HHIA “may” challenge an administrative rule through a declaratory action “in the circuit court of the county in which [HHIA] ... has its principal place of business,” i.e., the fifth circuit court [hereinafter, “the county rule”]—(1) endows the fifth circuit court and only the fifth circuit court with subject matter jurisdiction over HHIA’s action, or (2) merely expands the general venue rule set forth in HRS § 603-36(5), see supra note 7. If the latter is true, the director’s motion was untimely and, accordingly, any venue defect was waived. If, on the other hand, the county rule is a restriction on subject matter jurisdiction, we must notice the first circuit court’s lack of subject matter jurisdiction sua sponte and vacate its decision.

The uncertainty of the meaning of the county rule springs from (1) its use of the word “may” rather than “shall” and (2) its *92silence with respect to whether the petitioner’s domicile controls venue or jurisdiction. HHIA might argue that HRS § 632-1 confers jurisdiction that is not conditioned upon any geographic factor: “In cases of actual controversy, courts of record, within the scope of their respective jurisdictions, shall have power to make binding adjudications of right.'... Relief by declaratory judgment may be granted in civil cases.... ” However, the phrase “within the scope of [the courts’] respective jurisdictions” simply begs the question of whether, in the case of HRS § 97-1(a), a given circuit court’s jurisdiction is contingent upon the plaintiffs domicile in the corresponding county.

Illustrative authority from Hawafi sources is succinct at best, but, in light of (1) the redundancy of the county rule if interpreted as a venue provision, (2) our interpretation of a similar statute in Hawaiian Tel. Co., and (3) the fact that the county rule accounts for only the convenience of the 'plaintiff, contrary to the usual purpose of a venue statute, we hold that, for purposes of declaratory actions brought pursuant to HRS § 91—7(a), the circuit court of the plaintiffs domicile is the only circuit court that may exercise jurisdiction over the subject matter.

B. Analysis

Admittedly, the legislature could have drafted the county rule using the word “shall” rather than “may,” so as to make its mandatory jurisdictional effect clearer. Nevertheless, we believe that “may,” in the context of the county rule, implies that bringing a declaratory action in the plaintiffs home forum is an alternative to (1) seeking injunc-tive or monetary relief or foregoing litigation altogether, not (2) seeldng declaratory judgment, but in another venue.

When it drafted the county rule, the House Judiciary Committee took as its point of departure the Model State Administrative Procedure Act of 1961, § 7 (superseded 1981), 15 U.L.A. 262 (2000 & Supp. 2006), which provided that “[t]he validity or applicability of a rule may be determined in an action for declaratory judgment in the [District Court of ... County]” (emphasis added) (some brackets added and some in original) (ellipsis in original), 15 U.L.A. 262. See Hse. Stand. Comm. Rep. No. 8, in 1961 House Journal, at 654-55, 658; Hse. Stand. Comm. Rep. No. 83, in 1959 House Journal, 1st Spec. Sess., at 224-26, 229. The committee report, which is itself ambiguous with respect to the significance of “may” and whether the designated county is an optional venue or a mandatory situs of jurisdiction, reads in relevant part:

[S]ection 7[ ] of the ... Model [APA] has been amended to provide that an interested person may obtain a declaratory judgment where the rule is invalid on the grounds [now set forth in HRS § 91-7(b) ]. As to where a proceeding can be instituted, an interested person may bring an action where he resides, or in the case of a corporation where its principal place of business is located.

See Hse. Stand. Comm. Rep. No. 8, in 1961 House Journal, at 654-55, 658. We do not believe that the legislature, which retained the word “may” as used in the Model APA, intended to bestow an extra benefit upon HRS § 91-7 plaintiffs that they “may” ignore if they prefer to sue outside of their own domiciles.

Nevertheless, whether the county rule is “mandatory” or not, in and of itself, does not settle the question whether the plaintiffs failure to file in the prescribed county is a fatal jurisdictional defect or a venue defect capable of being waived.

We agree with the director’s implicit position that subject matter jurisdiction, not just venue, may be partitioned along county lines. In Hawaiian Tel. Co., we construed similar “[plaintiff] may file X in the county in which Y” syntax as mandatory and jurisdictional. In that case, we considered the first sentence of HRS § 383-38 (Supp. 1977), which provided that an unemployment benefits claimant “may file an appeal from [a] determination or redetermination at the office of the department of labor and industrial relations in the county in which the claimant resides or in the county in which the claimant was last employed" (emphases added), and expressly held that filing a notice of *93appeal in the wrong circuit was a defect of jurisdiction and not venue. See 67 Haw. at 40, 675 P.2d at 778. Accordingly, we upheld the circuit court’s dismissal of the appellant’s appeals from decisions of the Department of Labor and Industrial Relations. Id.

We likewise agree with HHIA that HRS § 603-36(5) delineates permissible venues and is not a geographic limitation on jurisdiction, which befits its codification in HRS eh. 603, pt. IV, concerning “venue” in the “circuit courts.” Kaui v. County of Kauai, 47 Haw. 271, 386 P.2d 880 (1963), illustrates the distinction between HRS §§ 91-7(a), see supra note 3, and 603-36(5), see supra note 7. Kaui concerned 1957 Haw. Sess. L. Act 194, 47 Haw. at 272, 386 P.2d at 882, which was a forerunner of HRS § 603-36(5).11 We construed Act 194 as a venue statute and, accordingly, remanded for determination of the factual question of whether the defendant county had waived its venue objection. See id. at 274, 276, 386 P.2d at 882-83. We opined that Act 194 “could not have been intended to go to jurisdiction over the subject matter as it permits an action to be brought where the defendant is domiciled without regard to the place where the cause of action arose.” Id. at 276, 386 P.2d at 883 (emphasis added). The inverse is true of HRS § 91-7(a): that the appropriate forum for litigation under HRS § 91-7(a) is predicated solely upon the plaintiffs residence and without regard to either the agency’s convenience or the nature or location of the parties’ interaction strongly suggests that the county rule is one of jurisdiction and not venue. Cf. id. at 276, 386 P.2d at 884 (“Considering the sweeping nature of [Act 194,] no policy other than protection of defendants from harassment can be discerned.... [W]hat is for the protection of a defendant may be waived by him.”), followed by Alamida v. Wilson, 53 Haw. 398, 400-01, 495 P.2d 585, 588 (1972).

IV. CONCLUSION

In light of the foregoing analysis, we hold that a plaintiff seeking “a judicial declaration as to the validity of an agency rule,” pursuant to HRS § 91-7, must “reside[ ] or ha[ve] its principal place of business” in the county in which the adjudicating circuit court sits; initiating an HRS § 91-7 action in the wrong circuit is a defect of jurisdiction mandating dismissal. Accordingly, we vacate the first circuit court’s judgment and remand with instructions to dismiss HHIA’s declaratory action.

Concurring Opinion by

I concur in the result but on the ground that Hawaii Revised Statutes (HRS) § 91-7 (1993) on its face is specific and thus plainly and unambiguously controls as to Plaintiff-Appellant Hawaii Home Infusion Associates’ particular “petition” for declaratory review of an agency rule. See Richardson v. City and County of Honolulu, 76 Hawai'i 46, 55, 868 P.2d 1193, 1202 (1994) (stating that, “ *where there is a ‘plainly irreconcilable’ conflict between a general and a specific statute concerning the same subject matter, the specific •will be favored’ ” (quoting Mahiai v. Suwa, 69 Haw. 349, 356-57, 742 P.2d 359, 366 (1987) (citations omitted))). Because HRS § 91-7 is the applicable statute, “may” must be construed as compulsory, i.e., allowing a judicial declaration upon the filing of a petition in the circuit court of the affected county, rather than as indicating an alternative basis for jurisdiction. See Kepo'o v. Kane, 106 Hawai'i 270, 288 n. 30, 103 P.3d 939, 957 n. 30 (2005) (stating that “ ‘[m]ay’ is also defined as ‘shall, must—used especially in deeds, contracts, and statutes’ ” (brackets and citation omitted)); cf. Lingle v. Hawai'i Gov’t Employees Ass’n, AFSCME, Local 152, 107 Hawai'i 178, 187 & n. 1, 111 P.3d 587, 596 & n. 1 (2005) (Acoba, J., concurring) (stating that HRS § 91-8 (1993), which provides that *94“ ‘[a]ny interested person may petition an agency for a declaratory order as to the applicability of any statutory provision or of any rule or order of the agency[,]’ ” must be construed as “authorizing] interested persons to petition agencies for declaratory rulings” (emphases added)).