La Grande is a city in Union County, Oregon, United States. Originally named 'Brownsville,' it was forced to change its name due to that name already being used for a city in Linn County. Its current name comes from an early French settler, Charles Dause, who often used the phrase 'La Grande' to describe the area's beauty. The population was 12,327 at the 2000 census. The 2006 estimate is 12,540 residents. It is the county seat of Union County. La Grande lies east of the Blue Mountains and southeast of Pendleton. La Grande apartments for rent comparison page shows most up to date rent information on La Grande apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.