TN 2 is a giant V
1926 Official

TN 2 east out of Jasper 1928 Official

TN 2 southeast out of Jasper 1930 Official

Also about 1929, TN 2 was placed on today's Lee Hwy between Chattanooga and Summit. The old route eventually became the TN 2A corridor which was realigned in the 1930s. Today it is TN 17; Campbell St, Lightfoot Mill Rd; TN 317 (except TN 2 used abandoned routing between Noah Reid Rd and Bonnyvale Ln); Old Cleveland Pike (now ends at RR track); abandoned routing along north side of the RR; Old Cleveland Pike (just south of Volkswagon Dr interchange with I-75)
By 1930, TN 2 was removed from Old Dixie Hwy and Nelson Rd in Kimball.
In 1929 or 1930, TN 2 was rerouted in Chattanooga from Whiteside (this is Broad today)/Main/Cowart/Market/8th/Georgia/McCallie to Whiteside/11th/Central/McCallie.
In 1930 (bridge date), TN 2 was removed from Old Niota Rd out of Athens, plus a routing that is now essentially covered by TN 305 and US 11 (plus Club House Dr).
Also about 1930, TN 2 was removed from Browder School Rd/Huntsville Hollow Rd, plus Old Loudon Pike into Lenoir City
In 1931, TN 2 was put on new alignment between Bashaw Creek Rd across the Duck River to about Hendrixson Dr, leaving behind abandoned routing to the south.
Also in 1931 (bridge date), TN 2 was removed from Old Athens Pike/High St/Mayes Ave (no longer continous)/Old US 11 through Sweetwater; also Ol Lee Hwy/Elm St through Philadelphia
In 1931 or 1932, TN 2 was extended over TN 1 from Old Stage Rd to the new Lee Hwy routing at Dixie Lee Jct.
In 1931 or 1932, TN 2 was placed on current Old Lee Hwy and US 11-64 from Summit through the Ooltewah area. The old route is more Old Cleveland Pike (cut off by TN 317); Ooltewah Cemetary Rd/Jack Cate Rd/Lodge Ln/Railroad Ave/TN 321.

TN 2 meeting TN 58 east of Chattanooga 1928 Official

TN 2 meeting US 41 instead 1930 Official

TN 2 straightened out at Ooltewah 1934 Official

In 1935, TN 2 was removed from Oscar Cromwell Rd in Beechgrove; Old Beechgrove Rd and Ferrell's Cemetery Rd
Also about 1935, TN 2 was removed from the two Kellys Ferry segments west out of Lookout Valley; also removed from today's TN 318 and Old Wauhatchie Pike (no longer continuous)
In 1940, TN 2 was removed from French Brantley Rd southeast of Beechgrove and I believe also Old Murfreesboro Rd/Walter Barnes Ln (cutoff by I-24 from)/Busy Corner Ln
Also in 1940, TN 2 received its current routing through Charleston/Calhoun. The old route used Market St/Water St/remove bridge/Church St/Main St/TN 163/Old US 11
In the mid 1950s, TN 2 was rerouted in Murfreesboro. Originally it ended at Main St at Maney Ave. Now, TN 2 was removed from Maney and extended northwest on newly constructed Broad St to end at US 70S/TN 1 College St.

TN 2 original Murfreesboro route 1939 Rutherford County

TN 2 modern Murfreesboro route 1960 Rutherford County

It is unclear when TN 2 was removed from Mabee Ave in Monteagle but my guess is the 1950s.
About 1953, TN 2 was given its bypass of Athens. The old route through town became secondary for a number of years before becoming TN 2 Bus. Today it is TN 39, TN 305, and CR 379.

TN 2 original Charleston to Sweetwater routing 1929 Official

TN 2 straightened north of Athens 1932 Official

TN 2 straightened out at Charleston/Calhoun 1943 Official

TN 2 bypasses Athens 1956 Gousha

My guess is that TN 2 was removed from Glover Hill Rd in Jasper in 1954.
In 1956 (bridge date), TN 2 was given one-way splits in Chattanooga. EB used 11th/Central/Bailey/Doods (replacing TN 2A #2) while WB used the original alignment of McCallie/Central/9th/Georgia (this became TN 2 Loop on the TN route log)
About 1958, TN 2 was given its current route through Manchester. Originally it used Irwin/High/Spring/Fort/Woodland Sts.
By 1961, the Chattanooga Splits were just Bailey EB and McCallie WB between Georgia and Dodds
About 1962, TN 2 was placed on I-75 between exits 7 and 11 northeast of Chattanooga. This created a split routing with NB using Bonnie Oaks Dr to access I-75 NB, while SB still used Lee Hwy on the west side of I-75 which had a ramp from I-75 SB about 3/4 of a mile north of Exit 7. This left behind Old Lee Hwy on the east side of the interstate.
Around 1964, TN 2 was removed from Dixie Lee Ave and a piece of Bluebird Ln south of Monteagle and placed onto I-24 EB lanes. I-24 EB was built more or less on top of TN 2 with just a few abandoned segments to smooth out some curves. At the bottom of the mountain, TN 2 was removed from Martin Springs Rd on the east side of I-24 to just south of the current TN 2 exit.
In the 1960s, TN 2 was truncated to the current routing of US 70S/TN 1 south of downtown Murfreesboro.
Around 1968, TN 2 was rerouted just west of the Tennessee River bridge Haletown to accommodate Nickajack Lake. Only a small bit of the original route within Marion County Park is not underwater.
In 1983, TN 2 was rerouted around Cleveland, replacing TN 2 Byp. The old route through town became TN 40 south of downtown and TN 74 north of it.

TN 2 through Cleveland 1980 Bradley County

TN 2 bypasses Cleveland 1985 Bradley County

About 2004, TN 2 was removed from central Chattanooga entirely by using 20th/23rd/Dodds. The old routing into downtown remains part of US 72 and TN 8. Leaving downtown on its former one-way pairs is no longer in the state highway system.

TN 2 using 8th 1928 Official

TN 2 using 11th 1932 Official

TN 2 on one-way splits 1968 Hamilton County

TN 2 moved to Dodds and 23rd 2009 Official

Also about 2004, TN 2 was removed from Lee Hwy north of Exit 7 on I-75 as the far flung ramp was removed and new ramps were installed right at Exit 7.
Posting: TN 2 is completely unposted, except for its solo section off I-24 near Kimball. The other solo segment between I-24 exit 135 and Monteagle is unposted. TN 2 is primary between I-75 Ooltewah and US 321 Lenoir City and secondary everywhere else.
Secret US Route Overlay: US 41 (55.4 mi)
US 64 (60.4 mi)
US 11 (63.9 mi)
Comment: TN 2 forms a V-shape with Chattanooga at the bottom point.
It appears that TN 2 had a railroad underpass of under 8 feet in Ooltewah until it was relocated to I-75.