ST. LOUIS • The National Geospatial-Intelligence Agency started with six possible locations to replace its existing Western Headquarters in St. Louis, and now they are down to four.

The agency said on Monday that it has dropped two locations, the NorthPark development in north St. Louis County and the Weldon Spring location near Chesterfield, from consideration. The agency said after initial reviews neither of the sites meet NGA requirements.

Now, the agency will conduct environmental reviews of the four remaining locations:

• Fenton (the site of the old Chrysler plant along Interstate 44)

• Mehlville (at the Met Life facility on Tesson Ferry Road, between Interstate 270 and Highway 141)

• North St. Louis (the site of the old Pruitt-Igoe housing complex near Cass and Jefferson avenues)

• St. Clair County (site adjacent to Scott Air Force Base along Interstate 64)