This is a colored, divided-back postcard of  U.S. ARMORED CRUISER "MARYLAND", (ACR-8/CA-8).  She was commission in 1905 and decommissioned in 1922; 
start of WW1 her name was changed to FREDERICK.  

Round dated Portland Ore June 5:30 p.m. 17, 1907
size 3 1/2 x 5 1/5