Grass Lake National Wildlife Refuge

{{Use mdy dates|date=January 2025}}

{{Infobox protected area

| name = Grass Lake National Wildlife Refuge

| iucn_category = IV

| photo =

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| map = USA

| relief = 1

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| location = Stillwater County, Montana, USA

| nearest_city = Billings, MT

| coordinates = {{coord|45|56|39|N|109|06|42|W|notes={{cite gnis|id=772073|name=Grass Lake National Wildlife Refuge|access-date=February 24, 2014}} |display=inline, title}}

| area = {{convert|4318|acre|abbr=on}}

| established = 1987

| visitation_num =

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| governing_body = U.S. Fish and Wildlife Service

| website = [https://www.fws.gov/refuge/Grass_Lake Grass Lake National Wildlife Refuge]

}}

Grass Lake National Wildlife Refuge (formerly Halfbreed Lake National Wildlife Refuge{{GNIS|772073}}) is in the central section of the U.S. state of Montana and is an integral part of the Charles M. Russell National Wildlife Refuge Complex, managed from the Charles M. Russell National Wildlife Refuge.{{cite map|publisher=Topoquest (USGS Quads)|title=Wheat Basin, MT|url=http://www.topoquest.com/map.php?lat=45.94828&lon=-109.10794&datum=nad83&zoom=4|access-date=February 24, 2014}}{{cite web|title=Annual Report of Lands Under Control of the U.S. Fish and Wildlife Service|url=http://www.fws.gov/refuges/realty/archives/pdf/2010_Annual_Report_of_Lands.pdf|format=pdf|page=23|publisher=U.S. Fish and Wildlife Service|date=September 30, 2010|access-date=February 24, 2014}} This refuge provides nesting habitat for migratory bird species.{{cite web|title=Halfbreed Lake National Wildlife Refuge|url=https://www.fws.gov/refuges/profiles/index.cfm?id=61522|publisher=U.S. Fish and Wildlife Service|access-date=February 24, 2014}}