Delta County is a county in the Upper Peninsula in the U.S. state of Michigan. As of the 2020 census, the population was 36,903. The county seat is Escanaba. The county was surveyed in 1843 and organized in 1861. Its name originates from the Greek letter delta (Δ), which refers to the triangular shape of the original county which included segments of Menominee, Dickinson, Iron, and Marquette counties. Recreation and forest products are major industries, and crops include hay, corn, small grains, potatoes, and strawberries.

Delta County comprises the Escanaba, MI Micropolitan Statistical Area.

According to the U.S. Census Bureau, the county has a total area of 1,991 square miles (5,160 km), of which 1,171 square miles (3,030 km) is land and 820 square miles (2,100 km) (41%) is water. It is the fifth-largest county in Michigan by land area.

By land

• Menominee County (southwest, Central Time Zone border)
• Marquette County (northwest)
• Alger County (north)
• Schoolcraft County (east)

By water

• Leelanau County (southeast)
• Door County, Wisconsin (south, Central Time Zone border)

• Hiawatha National Forest (part)

• Escanaba (county seat)
• Gladstone

• Garden

• A small section of the Hannahville Indian Community, which has most of its territory in neighboring Menominee County to the west, extends into Bark River Township.
• The Sault Tribe of Chippewa Indians occupies a very small portion in the southwest city limits of Escanaba.

Historical population

Census	Pop.	Note	%±
1860	1,172		—
1870	2,542		116.9%
1880	6,812		168.0%
1890	15,330		125.0%
1900	23,881		55.8%
1910	30,108		26.1%
1920	30,909		2.7%
1930	32,280		4.4%
1940	34,037		5.4%
1950	32,913		−3.3%
1960	34,298		4.2%
1970	35,924		4.7%
1980	38,947		8.4%
1990	37,780		−3.0%
2000	38,520		2.0%
2010	37,069		−3.8%
2020	36,903		−0.4%
2023 (est.)	36,790		−0.3%
US Decennial Census 1790-1960 1900-1990 1990-2000 2010-2018

The 2010 United States census indicated Delta County had population of 37,069. By 2020, its population was 36,903.

School districts include:

• Bark River-Harris School District
• Big Bay de Noc School District
• Escanaba Area Public Schools
• Gladstone Area Schools
• Mid Peninsula School District
• Rapid River Public Schools

United States presidential election results for Delta County, Michigan

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	14,109	64.43%	7,462	34.08%	326	1.49%
2020	13,207	62.39%	7,606	35.93%	354	1.67%
2016	11,121	59.81%	6,436	34.61%	1,037	5.58%
2012	9,534	52.59%	8,330	45.95%	266	1.47%
2008	8,763	45.97%	9,974	52.32%	327	1.72%
2004	9,680	50.32%	9,381	48.76%	177	0.92%
2000	8,871	51.23%	7,970	46.03%	475	2.74%
1996	5,925	36.69%	8,561	53.01%	1,664	10.30%
1992	6,027	33.55%	8,387	46.69%	3,548	19.75%
1988	7,114	44.28%	8,891	55.34%	60	0.37%
1984	8,952	52.84%	7,934	46.83%	56	0.33%
1980	8,146	46.04%	8,475	47.90%	1,071	6.05%
1976	7,809	45.85%	9,027	53.00%	197	1.16%
1972	7,647	48.14%	8,003	50.38%	236	1.49%
1968	5,829	40.58%	7,821	54.45%	714	4.97%
1964	4,434	30.56%	10,046	69.25%	27	0.19%
1960	6,460	44.82%	7,924	54.98%	29	0.20%
1956	7,766	54.31%	6,489	45.38%	45	0.31%
1952	7,488	51.79%	6,921	47.87%	49	0.34%
1948	5,414	42.86%	6,943	54.96%	276	2.18%
1944	5,213	41.23%	7,375	58.33%	56	0.44%
1940	6,218	41.18%	8,802	58.29%	81	0.54%
1936	4,527	32.83%	8,954	64.93%	310	2.25%
1932	4,386	35.70%	7,363	59.93%	536	4.36%
1928	5,420	49.59%	5,419	49.58%	91	0.83%
1924	4,761	49.83%	463	4.85%	4,330	45.32%
1920	4,938	65.40%	1,985	26.29%	627	8.30%
1916	3,088	59.74%	1,781	34.46%	300	5.80%
1912	1,111	25.38%	1,066	24.35%	2,201	50.27%
1908	3,243	71.70%	1,097	24.25%	183	4.05%
1904	3,332	79.88%	658	15.78%	181	4.34%
1900	3,081	70.94%	1,210	27.86%	52	1.20%
1896	2,774	67.81%	1,237	30.24%	80	1.96%
1892	1,769	54.30%	1,412	43.34%	77	2.36%
1888	1,587	54.16%	1,332	45.46%	11	0.38%
1884	1,201	66.13%	609	33.54%	6	0.33%

Delta County operates the County jail, maintains rural roads, operates the major local courts, records deeds, mortgages, and vital records, administers public health regulations, and participates with the state in the provision of social services. The county board of commissioners controls the budget and has limited authority to make laws or ordinances. In Michigan, most local government functions – police and fire, building and zoning, tax assessment, street maintenance etc. – are the responsibility of individual cities and townships.

(information as of September 2018)

• US 2 runs east–west through the lower part of the county, entering from Schoolcraft County east of Garden Corners and running westward to an intersection with US 41 at Rapid River.
• US 41 runs north–south through central part of the county, entering from Alger County at Trenary, running southerly to Rapid River then southwesterly along the Lake Michigan shore to the southwest corner of county.
• M-35 enters from Marquette County at the northwest corner of the county and runs southeasterly to intersection with US 41 at Gladstone.
• M-69 runs east–west across the southwestern tip of the county, entering from Menominee County at Schaffer and running southeasterly to an intersection with US 41 west of Narenta.
• M-183 runs from the southern tip of the Garden Peninsula at Fayette State Park to an intersection with US 2 at Garden Corners.

The county is served by Delta County Airport (KESC), southwest of Escanaba. It provides scheduled airline service to Detroit and Minneapolis.

• List of Michigan State Historic Sites in Delta County, Michigan
• National Register of Historic Places listings in Delta County, Michigan

• Delta County government website
• Delta County Profile, Sam M Cohodas Regional Economist, Tawni Hunt Ferrarini, Ph.D. Archived July 14, 2020, at the Wayback Machine
• "Bibliography on Delta County". Clarke Historical Library, Central Michigan University.

45°47′N 86°52′W / 45.78°N 86.87°W / 45.78; -86.87