Answer (1):

Zig

The Federal Reserve

However, they shouldn't exist. They do a crappy job causing boom and bust cycles, artificially low interest rates cause inflation and devalue our money. Way too much power in regulating the economy for my liking!

The Federal Reserve officially identifies Districts by number and Reserve Bank city.[13]

1st District (A) - Federal Reserve Bank of Boston
2nd District (B) - Federal Reserve Bank of New York
3rd District (C) - Federal Reserve Bank of Philadelphia
4th District (D) - Federal Reserve Bank of Cleveland, with branches in Cincinnati, Ohio and Pittsburgh, Pennsylvania
5th District (E) - Federal Reserve Bank of Richmond, with branches in Baltimore, Maryland and Charlotte, North Carolina
6th District (F) - Federal Reserve Bank of Atlanta, with branches in Birmingham, Alabama; Jacksonville, Florida; Miami, Florida; Nashville, Tennessee; and New Orleans, Louisiana
7th District (G) - Federal Reserve Bank of Chicago, with a branch in Detroit, Michigan
8th District (H) - Federal Reserve Bank of St. Louis, with branches in Little Rock, Arkansas; Louisville, Kentucky; and Memphis, Tennessee
9th District (I) - Federal Reserve Bank of Minneapolis, with a branch in Helena, Montana
10th District (J) - Federal Reserve Bank of Kansas City, with branches in Denver, Colorado; Oklahoma City, Oklahoma; and Omaha, Nebraska
11th District (K) - Federal Reserve Bank of Dallas, with branches in El Paso, Texas; Houston, Texas; and San Antonio, Texas
12th District (L) - Federal Reserve Bank of San Francisco, with branches in Los Angeles, California; Portland, Oregon; Salt Lake City, Utah; and Seattle, Washington