VA 411 near Winterpock 1929 Official

VA 411 renumbered as VA 409 1932 Official

VA 411 #2: Likely assigned as the state route designation for I-464 in the pre-construction days of Virginia interstate. It is not explicitly mentioned in the CTB Minutes but based on the 4xx routes that were mentioned, 411 fits the pattern established in association with the list of interstate corridors in Oct 1957. VA 411 #3: Appeared in March 1981 (CTB) as new primary routing, running on Rosemont Rd from VA 410 (now just Holland Rd) to US 58 in Virginia Beach just north of its interchange with VA 44 (now I-264). VA 411 was decommissioned in Jan 2001 (CTB). It was not posted anywhere while it was active. VA 411 #4: Created in Nov 2000 (CTB) when the VDOT 2020 transportatin plan was created, which included a road called the Tri-County Parkway. It began at the VA 234 Business/Godwin Dr intersection, skirted around the Manassas Battlefield, crossed US 50 at the SR 606 intersection and ended at VA 267 Dulles Greenway northwest of SR 606. The length of the road is 20.0 miles. In Dec 2000 (CTB), the section of SR 606 between US 50 and SR 621 which would be part of the Parkway (the only existing road to be a part), was formally removed from the primary system, technically splitting VA 411 into two piece totaling 19.2 miles.

VA 411 in Virginia Beach 1986 Official

Southern half of proposed VA 411 Nov 2000 CTB document

Northern half of proposed VA 411 with removed section (southern half was unchanged) Dec 2000 CTB document

In June 2001 (CTB), the number 411 was actually assigned to the Tri-County Parkway.
VA 411 was listed in 2001 and 2003 VDOT route logs: "From Route 234 in Prince William County to Route 50 in Loudoun County and from Route 621 in Loudoun County to the Dulles Greenway Parkway in Loudoun County (Tri-County Parkway). (Proposed)"
In Oct 2002, per this document, the Tri-County Pkwy was extended along Godwin Dr south to end at the VA 28/VA 234 Bypass interchange.
Per VDOT's website, in Nov 2005, the CTB approved the location for a new 10.4 mile north-south transportation link that would connect Manassas with the Dulles corridor. The location of the new road would be north of I-66 from the I-66 and Route 234 interchange to Route 50 in Loudoun County. The possible paths that were studied are shown here (pdf). The chosen path is segments C and D, roughly paralleling SRs 705 and 616 and runs 10.4 miles. The website says the Final Environmental Impact Statement is expected to be approved by the Federal highway Administration in fall of 2010. Note that this selection had no overlap with the Tri-County Pkwy as approved in 2001.
The Nov 2005 CTB minutes says it will be limited access but does not mention a route number for the route. The selection of segment D overlaps the Manassas Battlefield Bypass that is desired in order to remove VA 234 from the Battlefield.
I could not find anywhere on VDOT's website any mention of what happened to the SR 621 to Dulles Greenway segment, although the June 2013 public meeting on the Bi-County Pkwy does mention a study underway to extend it north of US 50 and east over to SR 606 to help serve Dulles and the upcoming Silver line. Additionally, the VTrans 2035 document from Nov 2010 does still mention VA 411 being on the future Loudoun County Pkwy from SR 621 to SR 772, as well as being on the moved location of what is now the Bi-County Pkwy. A small bit of the Loudoun County Pkwy in this defined area is built and appears to be signed as SR 607.
In Feb 2013 (CTB), the Tri-County Pkwy (still called this then even though Fairfax County is no longer in the path) from I-66/VA 234 Byp interchange north to VA 234 was essentially described such that it will be VA 234 when built.
Later in 2013 the project begins to be referenced as the Bi-County Pkwy instead.
Public meeting brochures from Sept/Oct 2013 imply the entire Bi-County Pkwy will be VA 234. There is an FAQ that talks about what will happen to 234 through the Battlefield but there is no mention of what would happen to VA 234 from Catharpin to US 15 and whether it would remain in the primary system or not.
In March 2016, Prince William County voted to remove the roadway from the county plans.
In 2022, the parkway was reintroduced into Prince William County discussions.