6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANTTO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of June 2026

Commission File Number: 000-55607

First MiningGold Corp.

(Translation of registrant's name into English)

Suite 2070, 1188 West Georgia Street, Vancouver, B.C., V6E4A2

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☐     Form 40-F ☒

DOCUMENTS FILED AS PART OF THIS FORM 6-K

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

First Mining and Slate Falls Nation Agree to Key Terms of Project Agreement for Springpole Gold Project

VANCOUVER, BC, June 30, 2026 /CNW/ - First MiningGold Corp. ("First Mining" or the "Company") (TSX: FF) (OTCQX: FFMGF) (FRANKFURT: FMG) is pleased to announce that it has entered into an agreement (the "Term Sheet Agreement") with Slate Falls Nation ("Slate Falls" or "SFN") containing the key terms upon which the parties will diligently negotiate a final project agreement (the "ProjectAgreement") for the Springpole Gold Project in northwestern Ontario, Canada ("Springpole" or the "Project").

The Term Sheet Agreement details SFN's development parameters for the Project, a collaborative process for advancing regulatory approvals and environmental protections, and mechanisms and structures for SFN to participate in future project design optimizations focused on robust environmental sustainability, as well as to participate in financial and business opportunities at the future mine. The Term Sheet Agreement has been endorsed by Slate Falls Chief and Council and commits the parties to diligently working to finalize the Project Agreement.

The Project Agreement will be subject to final approval by SFN Chief and Council and to approval by the Board of Directors of First Mining.

About Slate Falls Nation

Slate Falls Nation is a close-knit Ojibway First Nation based in northwestern Ontario, Canada, with a registered population of approximately 260 members. The majority of Slate Falls members live on reserve on the shores of Bamaji Lake directly downstream from the Project. The Nation's reserve is in the heart of the Cat River watershed, and Slate Falls people continue to rely on the water and the land for food, water, culture, spirituality, and identity. Anishinaabe laws guide all aspects of Slate Falls' life. Those laws are grounded in core principles and values which include responsibilities to protect the environment and live in harmony with it. Slate Falls is a Treaty 9 Nation, as well as a signatory to the Cat Lake–Slate Falls Community-Based Land Use Plan: "Niigaan Bimaadiziwin" – A Future Life, which sets a course for protection of important waterways and natural and cultural heritage features and offers certainty for sustainable economic development.

About First Mining Gold Corp.

First Mining is a gold developer advancing two of the largest gold projects in Canada, the Springpole Gold Project in northwestern Ontario, where permitting activities are on-going with a final Environmental Impact Statement / Environmental Assessment for the project submitted in November 2024, and the Duparquet Gold Project in Quebec, a PEA-stage development project located on the Destor-Porcupine Fault Zone in the prolific Abitibi region. First Mining also owns a 20% project interest in the Pickle Crow Gold Project in Ontario and large equity interest in Seva Mining Corp.

First Mining was established in 2015 by Mr. Keith Neumeyer, founder and CEO of First Majestic Silver Corp.

ON BEHALF OF FIRST MINING GOLD CORP.

Daniel W. Wilton

Chief Executive Officer and Director

Cautionary Note Regarding Forward-Looking Statements

This news release includes certain "forward-lookinginformation" and "forward-looking statements" (collectively "forward-looking statements") within the meaningof applicable Canadian and United States securities legislation including the United States Private Securities Litigation Reform Act of1995. These forward-looking statements are made as of the date of this news release. Forward-looking statements are frequently, but notalways, identified by words such as "expects", "anticipates", "believes", "plans", "projects","intends", "estimates", "envisages", "potential", "possible", "strategy","goals", "opportunities", "objectives", or variations thereof or stating that certain actions, events orresults "may", "could", "would", "might" or "will" be taken, occur or be achieved, orthe negative of any of these terms and similar expressions.

Forward-looking statements in this news releaserelate to future events or future performance and reflect current estimates, predictions, expectations or beliefs regarding future events.All forward-looking statements are based on First Mining's or its consultants' current beliefs as well as various assumptions made bythem and information currently available to them. There can be no assurance that such statements will prove to be accurate, and actualresults and future events could differ materially from those anticipated in such statements. Forward-looking statements in this news releaseinclude, but are not limited to, statements with respect to: entering into a Project Agreement with SFN; feasibility and permitting activitiesrelated to the Springpole Gold Project; realizing the value of the Company's gold projects for the Company's shareholders; Company'sbusiness strategy; future planning processes. Statements concerning proven and probable mineral reserves and mineral resource estimatesmay also be deemed to constitute forward-looking statements to the extent that they involve estimates of the mineralization that willbe encountered as and if the property is developed, and in the case of measured and indicated mineral resources or proven and probablemineral reserves, such statements reflect the conclusion based on certain assumptions that the mineral deposit can be economically exploited.

Forward-looking statements reflect the beliefs,opinions and projections of management on the date the statements are made and are based upon a number of assumptions and estimates that,while considered reasonable by the respective parties, are inherently subject to significant business, economic, competitive, politicaland social uncertainties and contingencies. Such factors include, without limitation the Company's business, operations and financialcondition potentially being materially adversely affected by the outbreak of epidemics, pandemics or other health crises, and by reactionsby government and private actors to such outbreaks; risks to employee health and safety as a result of the outbreak of epidemics, includingpandemics or other health crises, that may result in a slowdown or temporary suspension of operations at some or all of the Company'smineral properties as well as its head office; fluctuations in the spot and forward price of gold, silver, base metals or certainother commodities; fluctuations in the currency markets (such as the Canadian dollar versus the U.S. dollar); changes in national andlocal government, legislation, taxation, controls, regulations and political or economic developments; requirements for additional capital;changes in project parameters as plans continue to be refined; variations in ore reserves, grade or recovery rates; actual performanceof plant, equipment or processes relative to specifications and expectations; risks and hazards associated with the business of mineralexploration, development and mining (including environmental hazards, industrial accidents, unusual or unexpected formations, pressures,cave-ins and flooding); effectiveness of environmental mitigations and strategies including production of NAG and PAG tailings and minerock and water management strategies, the presence of laws and regulations that may impose restrictions on mining; employee relations;relationships with and claims by local communities, indigenous populations and other stakeholders; availability and increasing costs associatedwith mining inputs and labour; the speculative nature of mineral exploration and development; title to properties; and the additionalrisks described in the Company's Annual Information Form for the year ended December 31, 2025 filed with the Canadian securities regulatoryauthorities under the Company's SEDAR+ profile at www.sedarplus.ca, and in the Company's Annual Report on Form 40-F filed with the SECon EDGAR.

First Mining cautions that the foregoing list offactors that may affect future results is not exhaustive. When relying on our forward-looking statements to make decisions with respectto First Mining, investors and others should carefully consider the foregoing factors and other uncertainties and potential events. FirstMining does not undertake to update any forward-looking statement, whether written or oral, that may be made from time to time by theCompany or on our behalf, except as required by law.

Cautionary Note to United States Investors

The Company is a "foreign private issuer"as defined in Rule 3b-4 under the United States Securities Exchange Act of 1934, as amended, and is eligible to rely upon the Canada-U.S.Multi-Jurisdictional Disclosure System, and is therefore permitted to prepare the technical information contained herein in accordancewith the requirements of the securities laws in effect in Canada, which differ from the requirements of the securities laws currentlyin effect in the United States. Accordingly, information concerning mineral deposits set forth herein may not be comparable with informationmade public by companies that report in accordance with U.S. standards.

Technical disclosure contained in this news releasehas not been prepared in accordance with the requirements of United States securities laws and uses terms that comply with reporting standardsin Canada with certain estimates prepared in accordance with NI 43-101.

NI 43-101 is a rule developed by the Canadian SecuritiesAdministrators that establishes standards for all public disclosure an issuer makes of scientific and technical information concerningthe issuer's material mineral projects.

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SOURCE First Mining Gold Corp.

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%CIK: 0001641229

For further information: For further information, please contact: Toll Free: 1 844 306 8827, Email: [email protected]; Paul Morris, Director, Investor Relations, Email: [email protected]

CO: First Mining Gold Corp.

CNW 16:46e 30-JUN-26