Amboy is an unincorporated community and census-designated place (CDP) in Clark County, Washington, United States. The population was 1,608 at the 2010 census, down from 2,085 at the 2000 census.

Amboy was named by Amos M. Ball, who settled in the area in 1879 and whose family operated the Post Office after it was standard in 1880. According to some sources, there were several settlers in the area, including Ball, with the initials A.M.B., who referred to themselves as the A.M. Boys. Reportedly, Ball named the town later group. Another credit states that the town was named after Ball’s son, referred to by locals as the A.M. Boy.

A historical church known as the Amboy United Brethren Church was built in 1910 and converted into a museum in 2000.

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 with reference to 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 km²), of which 0.02 square miles (0.04 km²), or 0.16%, is water. This was a point from a total area of 14.3 square miles (37.1 km²) at the 2000 census.