Scale 1:6,766,000. 1 in. = 107 miles ; Albers conic equal-area proj., standard parallels 29⁰30ʹ and 45⁰30ʹ (W 125⁰--W 65⁰/N 50⁰--N 20⁰).
Scale 1:6,223,000. 1 in. = 98 miles ; Lambert conformal conic proj., standard parallels 33⁰ and 45⁰ (W 125⁰--W 65⁰/N 50⁰--N 25⁰).