This map is Territorial Growth 1775 from the U.S. National Atlas, 1970. The thirteen colonies are shown in the shaded area. The rest of the the British claims extend west to the Mississippi. Spain claim the land west of the Mississippi. Maine is part of Massachusetts. Vermont is claimed by New York but will wage its own revolution within the Revolution to become a de facto state.
Source: This map was downloaded from the Perry-Castañeda Library Map Collection of the University of Texas at Austin.