NML - USCG Radio Station - St. Louis, MO
St. Louis Coast Guard Station - Home of NML
Under an earlier USCG organization St. Louis was the headquarters for USCG District 2 (since abolished). This district included all of the Missouri, Ohio, Tennessee and Cumberland rivers, and the Mississippi from St. Paul to somewhat below Memphis.
Wess Wessling's USCG Patch Archive has these two patches for Base St. Louis: Pre 1981 Patch and Pre 1985 Patch.