TN 56 Monteagle to McMinnville 1924 Official

TN 56 extended north to Smithville 1926 Official

TN 56 extended north to Kentucky 1929 Official

TN 56 extended south to Alabama 1932 Official

In 1934, TN 56 was removed from Scott Rd north of Steppsville; Byars Rd well east of McMinnville; Old Beersheba Rd east of McMinnville
In 1936, TN 56 was removed from Jake Summers Rd which used to connect back to TN 56 at Ford Spring Rd jct north of Sherwood.
Between 1939-47, TN 56 was removed from Maple St in Sewanee.
In 1940, TN 56 was removed from Albert Knight Rd north of Beersheba Springs; removed from Wanamaker Ln at the Warren/Grundy Line
In 1941, TN 56 was placed onto Main St into McMinnville. The old route used Bridge St to S. Chancery St.
Between 1941-47, TN 56 was removed from Missouri Ave/Airport Rd/TN 156/Midway Rd east out of Sewanee. Northeast of Otter Falls Rd is abandoned.
In 1949, TN 56 got its bridge over Caney Fork Lake. The old route used Loves Ferry (Floating Mill Rd north of the lake and Baron Bluff Rd south of the lake).
I'm guessing about 1950 TN 53-56 was removed from Murray St in Gainesboro, which used to connect to TN 53-56 at the north end of Birch St.
In 1953, TN 56 was placed on newly constructed alignment from McMinnville to just short of DeKalb County line. The old route is N. Chancery St/Old Smithville Rd/Este Griffith Rd/Mitchell Rd; abandoned route e of TN 56; Mike Muncy Rd; abandoned route w of 56/Bessie Gribble Rd
Between 1957-59, TN 56 was rerouted at Baxter to avoid Double Springs, leaving behind US 70N and TN 56A (now TN 291).
In 1960, TN 56 was removed from Cronover Rd/abandoned Crow Creek crossing/now a driveway at Anderson near the Alabama line.
Also about 1960, TN 56 was removed from Fisher Rd at today's I-40 Exit 276.
By 1963, TN 56 was removed from Carthage Rd/Main St loop in south Red Boiling Springs and McClure St in Red Boiling Springs
In 1963, TN 56 was removed from McCoinsville Rd through McCoinsville and School Dr south of Gainesboro
In 1964, TN 56 was removed from Old State Hwy 56 in Cumberland Heights.
In the mid-1970s, TN 56 was removed from the looping University Ave in Sewanee; also removed from Old State Rt 56 in Coalmont
In 1966, TN 56 was removed from Magnolia Ln south of Smithville
In 1968, TN 56 was moved onto I-40 (which had already opened by 1964). The old route used Old Baxter Rd, then Main St, Dunvain Dr and Old SR 56 thgough Baxter.

TN 56 via Double Springs 1956 Gousha

TN 56 removed from Double Springs 1959 Official

TN 56 moved onto I-40 and bypasses Baxter 1971 Official

In the late 1960s, TN 56 was removed from Old Gainesboro Rd in Bloomington Springs as well as Bethel Park Rd just inside Jackson County; also removed from Herbert Johnson Cir/Biss Johnson Cir, Lee Fox Cir, James Stafford Rd, Hubert Brown Cir and Pap Johnson Cir north of Center Grove
In 1971, TN 56 received its bypass of central Smithville, leaving behind College St and Church St.
In 1972, TN 56 was removed from Main St and Hull Ave in Gainesboro.
In 1974, TN 56 was moved from Main St to Colville St in McMinnville.
In 1989, TN 56 was straightened out through North Springs
Posting: Posted as secondary routing south of Sewanee, between TN 80 and TN 151, and north of Red Boiling Springs; posted as primary routing everywhere else.
TN 56 is not posted on I-40 itself. The US 41A and US 41 overlays are also unposted.
The TN 53 overlay is posted.
Secret US Route Overlay: US 41 (6.3 mi)
Comment: TN 56 is the major state route N-S corridor in east central Tennessee.
It is puzzling that TN 56 has not been rerouted over TN 151 to Red Boiling Springs.