Stop Here on Red Sign
MUTCD R10-6
Stop at this point when the traffic signal is red.
What it looks like
A vertical white rectangle with black legend reading STOP HERE ON RED, sometimes shown with a stop-bar symbol.
When you'll see it
Posted at signalized intersections where the stop line sits well back from the signal, such as beside a crosswalk or railroad track.
What to do
When the traffic signal is red you must stop at this marked point rather than pulling forward closer to the intersection.
Related signs
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.