County resources:

Connecticut
Statehood: 9 Jan 1788
5th state of the United States
Bordering states:
North: Massachusetts
East: Rhode Island
West: New York
Capital: Hartford
Largest city: Bridgeport
Map: Connecticut, 1796
(click map to enlarge)
Library of Congress, Geography and Map Division
Counties: Original counties at time of statehood: Fairfield, Hrtford, Litchfield, Middlesex, New Haven, New London, Tolland, and Windham. Connecticut County Creation Dates and Parent Counties. Counties in 2020: 8.
Institutions, Societies, and Government Websites
Center for Connecticut Studies, Eastern Connecticut State University
Center for Connecticut Studies, Eastern Connecticut State University
Connecticut Historical Society
Connecticut Irish-American Historical Society
Connecticut Society of Genealogists, Inc.
Connecticut State Library Digital Collection
List of Connecticut Towns & Counties, Connecticut State Library
Museum of Connecticut History, Connecticut State Library Digital Collection
Newspapers of Connecticut, Connecticut State Library Digital Collection
Hartford County
Newspapers
Newspapers Archive: Connecticut
Chronicling America, digitized: Connecticut
Community History Archive Newspapers: Connecticut
Small Town Newspapers
(No Connecticut listings)
Additional websites
Record Sets-State Level
Connecticut Record Sets
(Ancestry Collections)
Connecticut Record Sets (Family Search)
Vital Records
Marriages
Connecticut Vital Records — Index of Marriages, 1897-1969
(Connecticut State Library)
Connecticut, U.S., Marriage Index, 1620-1926 (Ancestry)
Deaths
Connecticut Death Records Index, 1897-1969
(Connecticut State Library)
Connecticut, U.S., Deaths and Burials Index, 1650-1934 (Ancestry)
U.S., Social Security Applications and Claims Index, 1936-2007 (Ancestry)
Virtual Libraries
State of Connecticut
Genealogical and family history of the state of Connecticut, William Richard Cutter, 1911
Historical and Descriptive Sketches of the Counties, Cities and Principal Towns of the Six New England States, vol. 1, Massachusetts, Connecticut, Rhode Island, Rev. R. H. Howard, A.M. and Prof. Henry E. Crocker, 1880.
Litchfield County
General history of the town of Sharon, Litchfield county, Conn. from its first settlement, Charles F. Sedgwick, A. M., 1877.
Windham County
History of Windham County, Connecticut, Richard M. Bayles, 1889.
Maps
Connecticut Maps, Library of Congress
Connecticut Landowner Maps, Library of Congress
Interactive Map of Connecticut County Formation History, Maps of U.S.
Historical Maps Works: Connecticut
Manuscripts
Connecticut Manuscripts, Archive Grid
Connecticut Manuscripts, Library of Congress