Franklin County is a county located in the U.S. state of Washington. As of the 2020 census, its population was 96,749. The county seat and most populous city is Pasco. The county was formed out of Whitman County on November 28, 1883, and is named for Benjamin Franklin.

Franklin County is included in the Tri-Cities metropolitan area. Together, Kennewick, Richland and Pasco comprise Washington's Tri-Cities.

According to the United States Census Bureau, the county has a total area of 1,265 square miles (3,280 km), of which 1,242 square miles (3,220 km) is land and 23 square miles (60 km) (1.8%) is water.

• Columbia River
• Hanford Nuclear Reservation
• Juniper Dunes Wilderness
• Snake River

• SR 260
• Interstate 182
• U.S. 12
• U.S. 395

• Adams County - north
• Whitman County - east
• Walla Walla County - southeast
• Columbia County - southeast
• Benton County - southwest
• Grant County - northwest

• Hanford Reach National Monument (part)
• Saddle Mountain National Wildlife Refuge (part)

Historical population

Census	Pop.	Note	%±
1890	696		—
1900	486		−30.2%
1910	5,153		960.3%
1920	5,877		14.1%
1930	6,137		4.4%
1940	6,307		2.8%
1950	13,563		115.0%
1960	23,342		72.1%
1970	25,816		10.6%
1980	35,025		35.7%
1990	37,473		7.0%
2000	49,347		31.7%
2010	78,163		58.4%
2020	96,749		23.8%
2023 (est.)	99,034		2.4%
U.S. Decennial Census 1790–1960 1900–1990 1990–2000 2010–2020

Franklin County, along with Adams County, have the highest per capita percentage of Latino residents in the state.

As of the 2020 census, there were 96,749 people, 28,748 households, and 22,355 families residing in the county.

As of the 2010 census, there were 78,163 people, 23,245 households, and 18,163 families residing in the county. The population density was 62.9 inhabitants per square mile (24.3/km). There were 24,423 housing units at an average density of 19.7 per square mile (7.6/km). The racial makeup of the county was 60.5% white, 1.9% black or African American, 1.8% Asian, 0.7% American Indian, 0.1% Pacific islander, 31.8% from other races, and 3.2% from two or more races. Those of Hispanic or Latino origin made up 51.2% of the population. In terms of ancestry, 13.1% were German, 6.8% were English, 6.5% were Irish, and 3.3% were American.

Of the 23,245 households, 49.9% had children under the age of 18 living with them, 57.9% were married couples living together, 13.4% had a female householder with no husband present, 21.9% were non-families, and 16.4% of all households were made up of individuals. The average household size was 3.28 and the average family size was 3.68. The median age was 28.4 years.

The median income for a household in the county was $47,749 and the median income for a family was $52,218. Males had a median income of $40,604 versus $29,517 for females. The per capita income for the county was $18,660. About 16.5% of families and 19.9% of the population were below the poverty line, including 25.6% of those under age 18 and 13.7% of those age 65 or over.

The 2019 county population is estimated to be 95,222, a 21.8% increase since 2010. This far outpaces Washington State's overall growth of 13.2% over the same time interval, and puts Franklin County among the fastest-growing counties in the nation.

In 2018 the county contained 28,647 housing units.

• Connell
• Kahlotus
• Mesa
• Pasco (county seat)

• Basin City
• West Pasco

• Eltopia
• Harder

Franklin County has a Board of County Commissioners which is the governmental authority of the county. The board consists of three commissioners; they are elected by the voters and serve four-year terms. Other elected county officials include Assessor, Auditor, Clerk, Coroner, Prosecuting Attorney, Sheriff, and Treasurer.

United States presidential election results for Franklin County, Washington

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	19,086	59.84%	11,884	37.26%	927	2.91%
2020	18,039	55.67%	13,340	41.17%	1,025	3.16%
2016	13,206	53.65%	8,886	36.10%	2,522	10.25%
2012	13,748	60.39%	8,398	36.89%	618	2.71%
2008	12,037	60.81%	7,361	37.19%	397	2.01%
2004	10,757	66.57%	5,188	32.11%	214	1.32%
2000	8,594	63.13%	4,653	34.18%	367	2.70%
1996	5,946	49.16%	4,961	41.01%	1,189	9.83%
1992	4,486	41.02%	3,743	34.22%	2,708	24.76%
1988	6,488	56.65%	4,772	41.67%	192	1.68%
1984	7,724	62.96%	4,328	35.28%	216	1.76%
1980	7,327	61.26%	3,719	31.09%	915	7.65%
1976	5,671	54.51%	4,369	42.00%	363	3.49%
1972	5,972	56.75%	3,867	36.75%	684	6.50%
1968	4,234	44.22%	4,038	42.17%	1,303	13.61%
1964	3,615	35.94%	6,375	63.38%	68	0.68%
1960	4,201	44.65%	5,156	54.80%	52	0.55%
1956	3,763	46.51%	4,322	53.42%	5	0.06%
1952	3,291	53.89%	2,798	45.82%	18	0.29%
1948	1,541	37.31%	2,525	61.14%	64	1.55%
1944	1,381	40.97%	1,974	58.56%	16	0.47%
1940	1,084	36.34%	1,868	62.62%	31	1.04%
1936	622	23.98%	1,784	68.77%	188	7.25%
1932	838	33.89%	1,540	62.27%	95	3.84%
1928	1,339	61.96%	799	36.97%	23	1.06%
1924	709	31.15%	237	10.41%	1,330	58.44%
1920	839	44.46%	571	30.26%	477	25.28%
1916	671	35.02%	1,110	57.93%	135	7.05%
1912	293	16.41%	612	34.29%	880	49.30%
1908	643	52.97%	485	39.95%	86	7.08%
1904	572	69.25%	223	27.00%	31	3.75%
1900	52	37.41%	81	58.27%	6	4.32%
1896	38	24.84%	113	73.86%	2	1.31%
1892	28	23.53%	54	45.38%	37	31.09%

Franklin is a strongly Republican county in Presidential elections. No Democratic presidential candidate has carried Franklin County since Lyndon B. Johnson’s 1964 landslide, and the last Democratic gubernatorial candidate it backed was Dixy Lee Ray in 1976.

• National Register of Historic Places listings in Franklin County, Washington

• An illustrated history of the Big Bend country : embracing Lincoln, Douglas, Adams, and Franklin counties, state of Washington. Western Historical Pub. Co. 1904.
• Available online through the Washington State Library's Classics in Washington History collection

• Franklin County, Washington at HistoryLink.org
• Tri-City Regional Chamber of Commerce

46°32′N 118°54′W / 46.54°N 118.90°W / 46.54; -118.90