It is endemic to the California Central Valley, where it grows in vernal pools and meadows.

Lasthenia fremontii is an annual herb approaching a maximum height near 35 centimeters.

The hairy stem may be branched or not and it bears linear or few-lobed leaves up to about 6 centimeters long.

Atop the stems are inflorescences of flower heads with hairy phyllaries.

The fruit is a hairy club-shaped achene less than 2 millimeters long.