ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No.1-34370WASTE CONNECTIONS,INC.(Exact name of registrant as specified in its charter)Ontario, Canada(State or other jurisdiction of incorporation or organization)98-1202763(I.R.S. Employer Identification No.)6220 Hwy 7, Suite 600WoodbridgeOntario L4H 4G3Canada(Address of principal executive offices)(905) 532-7510(Registrant’s telephone number, including area code)Securities registered pursuant to Section12(b)of the Act: Indicate by check mark if the registrant is not required to file reports pursuant to Section13 or Section15(d)of the Act.Yes◻No Indicate by check mark whether the registrant (1)has filed all reports required to be filed by Section13 or 15(d)of the Securities Exchange Act of 1934during the preceding 12months (or for such shorter period that the registrant was required to file such reports), and (2)has been subject to such filingrequirements for the past 90days.YesNo◻ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule405 ofRegulation S-T during the preceding 12months (or for such shorter period that the registrant was required to submit such files).YesNo◻ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or anemerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growthcompany” in Rule12b-2 of the Exchange Act. (Check one): If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any newor revised financial accounting standards provided pursuant to Section13(a)of the Exchange Act.◻ Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internalcontrol over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm thatprepared or issued its audit report. If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in thefiling reflect thecorrection of an error to previously issued financial statements.◻ Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensationreceived byany of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).◻ Indicate by check mark whether the registrant is a shell company (as defined in Rule12b-2 of the Exchange Act).Yes☐No As of June30, 2025, the aggregate market value of shares held by non-affiliates of the registrant, based on the closing sales price for the registrant’scommon shares, as reported on the New York Stock Exchange, was $48,127,773,335. Number of common shares outstanding as of February 2, 2026:255,681,232 Portions of the registrant’s definitive Management Information Circular and Proxy Statement for the 2026 Annual Meeting of Shareholders (whichwill be filed with the SEC pursuant to Regulation 14A of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and with the securitiescommissions or similar regulatory authorities in Canada within 120days after the end of our 2025 fiscalyear) are incorporated by reference into PartIIIhereof. WASTE CONNECTIONS,INC.ANNUAL REPORT ON FORM10-KTABLE OF CONTENTS 1.BUSINESS11A.RISK FACTORS331B.UNRESOLVED STAFF COMMENTS481C.CYBERSECURITY482.PROPERTIES493.LEGAL PROCEEDINGS494.MINE SAFETY DISCLOSURE49 5.MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED SHAREHOLDERMATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES506.[RESERVED]517.MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITIONAND RESULTS OF OPERATIONS527A.QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK768.FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA789.CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ONACCOUNTING AND FINANCIAL DISCLOSURE1429A.CONTROLS AND PROCEDURES1429B.OTHER INFORMATION1439C.DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENTINSPECTIONS143 10.DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE14311.EXECUTIVE COMPENSATION14312.SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS ANDMANAGEMENT AND RELATED SHAREHOLDER MATTERS14313.CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTORINDEPENDENCE14414.PRINCIPAL ACCOUNTANT FEES AND SERVICES144 PART IV15.EXHIBITS AND FINANCIAL STATEMENT SCHEDULES14416.FORM 10-K SUMMARY148 SIGNATURES149SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS150 PARTI ITEM 1.BUSINESS This Annual Report on Form 10-K contains forward-looking statements based