East Fork Dairy Creek begins at 45°47′18″N 123°02′29″W / 45.788446°N 123.041498°W / 45.788446; -123.041498 (Dairy Creek East Fork source) in Columbia County, slightly north of its border with Washington County, and flows generally south for 22 miles (35 km).

[4][7][8][9] Before railroads displaced river boats on the Tualatin, some steamships also worked the lower section of Dairy Creek, with plans to go as far up stream as Centerville.

[4][9] For roughly its first 6 miles (10 km), West Fork Dairy Creek flows south from near Tophill in northwestern Washington County.

At 12.3 miles (19.8 km) from the confluence, the stream passes United States Geological Survey (USGS) gauge 14205400.

[4][6][9] The USGS monitors the flow of East Fork Dairy Creek at a station near the unincorporated community of Meacham Corner, 12.3 miles (19.8 km) from the confluence with the west fork and about 23 miles (37 km) from the mouth of Dairy Creek.