Forest Grove is a city in Washington County, Oregon, United States, 25 miles (40 km) west of Portland. The population was 21,083 at the 2010 census.
Prior to the 1840s when Euro-Americans settled the area, the Atfalati band of the Kalapuya Native American tribe lived on the Tualatin Plains in what is now Forest Grove.In 1841, Alvin T. and Abigail Smith were among the earliest to use the Oregon Trail and settled on what was first known as West Tualatin Plain.They overwintered with Henry Harmon Spalding, arriving in what is now Forest Grove in the fall. Intending to be missionaries, they found little potential as most of the natives had succumbed to European diseases. Smith served as the community's first postmaster beginning on February 1, 1850, and his log cabin served as the post office.Previous post offices in the area were called Tuality Plains and Tualatin, with Forest Grove adopted on December 31, 1858. The city was platted in 1850.In 1860, the population reached 430, but declined to 396 in 1870. Forest Grove was incorporated by the state in 1872, the first in the county.