Wikipedia:WikiProject U.S. Roads/Connecticut/List of 1920s numbers

The main source for this list is the 1926 maps at [http://www.broermapsonline.org/members/NorthAmerica/UnitedStates/NewEngland/].

Routes 1-99

Route 1, NY to RI via New Haven, New London
Now U.S. Route 1
Route 2
Now U.S. Route 5
Route 3
Now Route 35, U.S. Route 7, U.S. Route 6
Route 4, NY to MA via Sharon, Salisbury
Now Route 343, Route 41
Route 8, Stratford to MA via Derby, Waterbury, Torrington, Winsted
Now Route 110, Route 8
Route 10, Saybrook to MA via Middletown, Hartford, Granby
Now Route 9, Route 99, Route 189, Route 10
Route 12
Now Route 32, Route 12
Route 17, MA to west of Westerly via Canaan, Winsted, Hartford, Colchester, Norwich
Now U.S. Route 7, U.S. Route 44, Route 2
Route 32
Now Route 12, Route 32, Route 19

Routes 101-199

Route 101, South Chaplin to RI
Now Route 198, US 44
Route 102, New London to Colchester
Now Route 85
Route 103, Central Village to RI
Now Route 14
Route 104, Middletown to Glastonbury
Now Route 17
Route 105, Thompsonville to Stafford Springs
Now Route 190
Route 106, Clinton to Higganum
Now Route 81
Route 107, Talcottville to West Ashford
Now Route 30 and Route 74
Route 108, South Manchester to MA
Now Tolland Turnpike and Route 83
Route 109, Bolton Notch to Phoenixville
Now US 44
Route 110, Hartford to MA
Now Route 159
Route 111, Waterbury to Willimantic
Now Meriden Road, Route 322, W. Main St, E. Main St, and Route 66
Route 112, Guilford to Middletown
Now Route 77 and Route 17
Route 113, Plainville to Hartford
Now Route 372, Route 71, and New Britain Ave
Route 114, New Haven to Durham
Now Route 17
Route 115, Hartford to Weatogue
Now Route 185
Route 116, Farmington to Granby via Simsbury
Now Route 10
Route 117, New Haven to Sandy Hook
Now Route 34
Route 118, New Haven to Milldale
Now Route 10
Route 119, NY to Danbury
Now US 6
Route 120, New Haven to Naugatuck
Now Route 63
Route 121, NY to Canaan
Now U.S. Route 44
Route 122, Newtown to Bridgeport
Now Route 25
Route 123, Cornwall to Avon
Now Route 4 and US 202
Route 124, Bridgeport to Danbury
Now Route 58
Route 125, Southbury to New Milford
Now Route 67
Route 126, Norwalk to Ridgefield
Now US 7
Route 127, Bulls Bridge to NY
Now Bulls Bridge Road
Route 128, Danbury to Torrington
Now US 202
Route 129, Gaylordsville to NY
Now Route 55
Route 130, Woodbury to Goshen
Now Route 61, Route 63
Route 131, NY to Sherman
Now Briggs Hill Road
Route 132, Cornwall to South Canaan
Now Route 43, Route 63
Route 133, north of Winsted to Granby
Now Route 20
Route 134, New Milford to Canaan
Now US 7
Route 135, New Haven to North Branford
Now Route 80, Route 139
Route 136, Danbury to Gaylordsville
Now Route 37, Route 39
Route 137, Pomfret Landing to Killingly
Now Route 101
Route 138, Farmington to Collinsville
Now Route 4, Route 179
Route 139, Killingly to RI
Now Route 101
Route 140, North Branford to North Guilford
Now Route 80
Route 141, Willimantic to Plainfield
Now Route 14, Route 14A
Route 142, Putnam to MA
Now Route 171, Route 169
Route 143, Ridgefield to NY
Now Route 116
Route 144, Wauregan to Brooklyn
Now Route 205
Route 145, New Milford to Shelton
old Ousatonic Turnpike (now gone)
Route 146, Mansfield Center to Storrs
Now Route 195
Route 147, Woodbridge to Southbury
Now Route 67
Route 148, East Haddam to North Westchester
Now Route 149
Route 149, Stafford Springs to MA
Now Route 190, Route 171
Route 150, Old Lyme to North Plain
Now Route 156
Route 151, Willington to MA
Now Route 320, Centre Pike, Route 197
Route 152, Washington to Cornwall
Now Route 45
Route 153, East Haddam to Norwich
Now Route 82
Route 154, Woodbury to Washington
Now Route 47
Route 155, Bulls Bridge to New Preston
Now Bulls Bridge Road, W. Meetinghouse Road, Barker Road, Cherniske Road
Route 156, Newtown to Brooksfield
Now Route 25
Route 157, Bristol to Farmington
Now US 6
Route 158, Redding Ridge to Newtown
old Newtown Turnpike
Route 159, New Milford to Washington
Now Route 109
Route 160, Unionville to Plainville
Now Route 177
Route 161, Bethel to Newtown
Now Route 302
Route 162, Berlin to New Britain
Now Route 372, Route 71
Route 163, Torrington to Burlington
Now Route 4
Route 164, Glastonbury to Manchester
Now Route 83
Route 165, Glastonbury
Now Route 94
Route 166, Vernon to Stafford
Now Route 30
Route 167, Haddam
Now Route 151
Route 168, Bozrah to Andover
Now Route 87
Route 169, Chester
Now Route 148
Route 170, Montville
Now New London Turnpike (local)
Route 171, East Haven to Branford
Now Route 142
Route 172, Waterbury to Bristol
Now Route 69
Route 173, Shelton
Now Route 110
Route 174, Winsted to MA
Now Route 183

Routes 301-399

Route 312, Torrington to Norfolk
Now Route 272