Johnston Street runs north-south between East Main Street and East Oak Avenue, situated just east of East Street and just west of Thomas Street. It intersects Depot Street and Alice Street, both of which run west only from Johnston Street.

Johnston Street has been planted with street trees by the city. The street trees include the invasive weed species Flowering Pear/Callery Pear (Pyrus calleryana). However, they also include Interior Live Oak (Quercus wislizeni), which is native to Woodland, and Modesto Ash/Arizona Ash (Fraxinus velutina), which is native to other parts of California. Other non-native street trees on Johnston Street include Chinese Hackberry (Celtis sinensis), Chitalpa Trees (Chitalpa tashkentensis), Honey Locust (Gleditsia triacanthos), Crape Myrtle (Lagerstroemia indica), and Chinese Pistache (Pistacia chinensis), London Plane (Platanus × hispanica), and Japanese Pagoda Tree (Sophora japonica).