[1] The headwaters of Poso Creek are located within the Sierra Nevada and the Sequoia National Forest, at elevations of up to 8,000 feet (2,400 m).

[5] Below the oil fields the creek emerges to the intensively farmed San Joaquin Valley, where it passes between Wasco and McFarland.

The creek is crossed by Highway 99 and the Southern Pacific Railroad at Famoso and by the Friant-Kern Canal a few miles downstream.

As a primarily rain fed stream, Poso Creek flows only seasonally (November to May) in its upper reaches, while the lower part is an ephemeral wash.[5] [6] The United States Geological Survey operated a stream gage on Poso Creek from 1959 to 1985, recording an average annual flow of 39 cubic feet per second (1.1 m3/s).

[7] The greatest flow was 6,700 cubic feet per second (190 m3/s) on February 25, 1969,[8] while the creek was dry for six straight months in 1977.