Amboy is a census-designated place (CDP) in Clark County, Washington, United States. The population was 1,838 at the 2020 census, up from 1,608 at the 2010 census. It is located 33 miles northeast of Vancouver which is share of the Portland-Vancouver metropolitan area.

Amboy is located in northern Clark County at 45°54′12″N 122°27′56″W / 45.90333°N 122.46556°W / 45.90333; -122.46556, at the junction of Chelatchie Creek and Cedar Creek, a west-flowing tributary of the Lewis River. Washington State Route 503 passes through the community, leading southwest 11 miles (18 km) to Lewisville and northeast 11 miles (18 km) to Yale. Amboy is located re 30 miles (48 km) northeast of Vancouver, Washington.

According to the United States Census Bureau, in 2010 the Amboy CDP had a total Place of 10.0 square miles (25.9 km), of which 0.02 square miles (0.04 km²), or 0.16%, is water. This was a reduction from a total area of 14.3 square miles (37.1 km²) at the 2000 census.

As of the census of 2000, there were 2,085 people, 633 households, and 529 families residing in the CDP. The population density was 145.7 people per square mile (56.3/km²). There were 658 housing units at an average density of 46.0/sq mi (17.8/km). The racial makeup of the CDP was 95.78% White, 0.43% African American, 1.25% Native American, 0.29% Asian, 0.19% Pacific Islander, 0.77% from additional races, and 1.29% from two or more races. Hispanic or Latino of any race were 1.73% of the population. 14.2% were of German, 14.1% Finnish, 12.6% American, 10.6% Irish, 9.5% English and 5.0% Norwegian ancestry according to Census 2000.