Middlesex County League wasn an independent league based in Connecticut.
1905 Chester, Deep River, Essex, Saybrook
1906 Chester, Deep River, East Hampton, Essex, Middletown, Saybrook
1907 Chester, Deep River, East Hampton, Essex, Middletown, Saybrook
1908 Chester, Deep River, East Hampton, Middletown,
1909 to 1913 Not sure if this League played
1914 Chester, Deep River, East Hampton, Essex, Moodus, Saybrook
1915 Chester, Deep River, East Hampton, Essex, Higganum, Moodus
1916 to 1931 Not sure if this League played
1932 Branford, Deep River, East Hampton, Meriden, Middletown, Portland
1933 No cities entered or left this league.
1934 No cities entered or left this league.
1935 No cities entered or left this league.
1936 No cities entered or left this league.
1937 No cities entered or left this league.
1938 Essex, Higganum and Sybrook entered the league; Porland left the league.
1939 No cities entered or left this league.