​Lane County was established Jan. 29, 1851. It was created from the southern part of Linn County and that portion of Benton County that was east of Umpqua County. Originally it covered all of southern Oregon east to the Rocky Mountains and south to the California border. It was named after the territory's first governor, Joseph Lane.

Lane County is situated in central western Oregon. It has been vastly reduced from its original size and shifted from its original location by several boundary changes. One of the first changes gave it access to the Pacific Ocean when it acquired the northern part of Umpqua County in 1853. With the creation of Wasco County in 1854, it lost all territory east of the Cascade Mountains. Minor boundary changes occurred with Douglas County in 1852, 1885, 1903, 1915, and 1917; with Linn County in 1907; and with Benton County in 1923. The county currently has 4,620 square miles and is bounded by Lincoln, Benton, and Linn Counties to the north; Deschutes and Klamath Counties to the east; Douglas County to the south; and the Pacific Ocean to the west. 

When the Territorial Legislature created Lane County, it did not designate a county seat. In the 1853 election four sites competed for the designation. The "Mulligan donation" received a majority vote; however, since it was contiguous to the "Skinner claim" both became part of the new county seat known as Eugene. The city takes its name from the early pioneer Eugene Skinner. 

The first courthouse was in a small board shanty used in 1852 to hold trials. The county clerk's building, constructed in 1853, was used until it became too small. This building has been moved several times and is now at the fairgrounds adjacent to the Lane County Historical Museum. The first courthouse was constructed in 1855 at a cost of $8,500. A second courthouse was completed in 1898, at a cost of under $50,000. The building was torn down in 1959 to make way for the current structure, which cost $2,146,350.  Planning is underway for a new courthouse in Eugene.

The government of Lane County originally consisted of a county judge, three commissioners, assessor, treasurer, and sheriff. A clerk and school superintendent were added later. The county judge's position was abolished in 1953. In 1963 Lane County became a home rule county. The charter system permits county government to exercise legislative authority. Only the three county commissioners, assessor and sheriff remained, all other elected positions were abolished. The sheriff assumed both the law enforcement and tax collection duties. In 1969 the number of commissioners was increased to five. The Lane County Local Boundary Commission was also created in 1969. The port district at the Port of Siuslaw in Florence was created in 1909. 

The 1860 census showed a population of 4,780. Since then it has seen steady, even rapid growth. The 2016 population of 365,940 represented an increase of 4% since 2010. In spite of this growth, the county dropped from the 2nd to the 4th most populous county in recent years. 

Historically, Lane County's economy has been based on timber and agriculture. Timber became important because the county is on the edge of Oregon's largest stand of timber. Agriculture grew because of the fertile soil and moderate climate that exists in the Willamette Valley, making it one of the most productive farming areas in the nation. However, with the reductions in timber harvesting and the continued population growth affecting many agricultural areas, there has been a change of emphasis in the economic development of the county. 

Growth in the next decades is predicted to shift away from forestry to services, health care, education, and trade. A major economic asset for the county is the University of Oregon in Eugene. Finally, with access to the mountains and the coast, tourism adds to the county's economic vitality.