The Connecticut State Library holds most pre-1920 probate estate papers. Most have been indexed in the Library's Probate Estate Papers Index. The index cards are arranged alphabetically by individual's last name, first names, then chronologically. The cards have the individual's name, town of residence, probate district, and list of items contained in the estate packet.
View the Index to Probate Estate Files
Most of the estate papers have been microfilmed. The microfilms are available here. Family Search has also digitized the microfilm. There are two collections; Probate files early to 1880 & Probate files 1881-1915.
Ancestry.com has also recently digitized much of the microfilm collection. Connecticut residents can search this remotely. (See the link below). See also our tab for Probate Record Volumes.