The incident happened around 2 a.m. Wednesday near the 10 Freeway interchange in the Baldwin Park area.
Video from the freeway shows the small black dog running loose along the road as officers tried to corral it. It eventually hid under a patrol car.
Officers tried for some time to coax the dog out before they got a hold of it. The dog was placed in a cardboard box before it was safely placed inside their car.
It's unclear how or why the dog was on the freeway.