Route 21

Route 21, the Odobasic Parkway, is a major secondary route connecting Eastwick, Postington, and Bloomford. The current Route 21 was originally signed as Route 6, until 1963 when Abbington requested that the designations of Route 6 and Route 21 be swapped.

Eastwick
Route 21 maintains a very short presence in Eastwick, connecting to Route 1 and the Ianistan Turnpike, indirectly. It starts at an incomplete intersection, originally designed to be a two-level interchange, allowing non-stop access between Route 1 North and Route 21 East. However, the lower level (Route 1) was never completed and instead requires northbound motorists on Route 1 to turn left to stay on their road and head towards the Ianistan Turnpike or continue straight onto Route 21. Here, Route 1 remains a two-lane road on both sides of the intersection, Route 21 starts as a four-lane divided highway with a speed limit of 50.

In Eastwick, Route 21 intersects with Intermunicipal Road (former Route 3). It then continues into Postington.

Between Eastwick and Main Street
Route 21 continues as a four- to six-lane divided highway with right-in/right-out intersections through Postington, until Main Street. Any roads on the left side of traffic are accessed by periodic U-turns, in a setup similar to that of US Route 1 in southern Rhode Island. Exceptions to this include the four-way intersection with Route 3 (Brightland Bridge Turnpike) and the three-way intersection with Main Street and the DeFelice Highway.

This road was theoretically conceived as Ianistan's first semi-limited-access highway in 1937 and was fully constructed in 1942. Prior to this, Route 21 (then Route 6) was a three-lane undivided road with a center turn lane for cross traffic. However, the route became more congested over time and therefore more unsafe, so the route was redeveloped into the highway it is today. The eastbound lanes are part of the original 1930s right of way.

Main Street and Route 21A
On the east side of Postington, Route 21 splits into two, Route 21 and Route 21A. Route 21A directly connects to Route 9 (Eastwick Avenue) and Route 43 (Bozrah-Montvale Expressway), following the Odobasic Parkway, with a speed limit of 45 MPH, while Route 21 turns north and follows Main Street, paralleling Route 9 to the west. Route 21 becomes a two-lane road while on Main Street, then intersects Route 9 at an interchange and immediately afterwards intersects with Route 43. Route 21's speed limit on the Main Street section is 35 MPH.

Route 43 Multiplex
After meeting with Route 43, Route 21 joins the expressway, heading back south towards the Odobasic Parkway. It reenters the Odobasic Parkway and heads into Bloomford, over the South-Central Crossing.

Bloomford
Route 21 enters Bloomford after crossing the Susquehanna River and then enters Bloomford State Park. Upon entering Bloomford, the speed limit increases to 55 MPH and Route 21 remains a four-lane divided highway, though the eastbound and westbound rights of way split and reach different elevations. Route 21 then enters an elaborate interchange with Route 41 (Cross-Ianistan Expressway) and meets with Sheffield Street (former Route 26) and Route 7 (Arlington Drive). Route 21 becomes a four-lane undivided road after meeting with Route 7 and then enters Bloomford Center, with a speed limit of 35 MPH. At the intersection of Route 5 (Spearsburg Avenue), Route 21 faces the Bloomford Municipal Building and then intersects with Route 39 (Leighton Boulevard), eventually coming to its end at Route 11, the Delaware Parkway, in Minuit State Park.