Question: What river is the weapons manufacturer that developed the M15 pistol located on?
Sentence (from "M15 pistol"): The M15 General Officers is a .45 ACP pistol developed by the U.S. Army's Rock Island Arsenal from stock M1911 pistols as a replacement for the aging Colt Model 1903 and Model 1908 Pocket Hammerless pistols.
Relevant evidence: Yes