Endpoints of
US Route 17

US 1 came into town from the north via Princess Anne Street, and then continued south by turning west on Lafayette Boulevard.  US 17 came in from the south on Dixon Street, so it could have ended south of downtown, at its junction with US 1 (Princess Anne and Lafayette).  However, there is photo evidence (not clear enough to post here) suggesting that US 17 was actually overlapped north with US 1 past the courthouse, ending at the junction with VA highway 3.  At the time, VA 3 ran along William Street, and in the early days it was common for highways to be overlapped into central business districts.  This interactive image is looking north on Princess Anne at William:

Until more information is found, the answer is unknown... although there are a couple reasons why it would have made sense to extend US 17 to the bypass.  This would have ensured that all US 1 traffic (mainline and bypass) had a connection to US 17.  And it would have brought US 17 traffic closer to VA 17 (which began right across the river in Falmouth).  Here is a more recent view from the same perspective:

In 1976 a separate bridge over the Peace River was opened for southbound US 41 traffic.  This bridge aligns with Cross Street, so at that time US 17 was extended about four blocks further south to its current terminus on Marion at Cross.  Approach signage on Marion (southbound US 17) looks like this:

The sign on the right indicated that US 11 continued straight on Braddock, which immediately turns into Valley Avenue and heads toward Harrisonburg.  (US 11 was the original highway serving the Shenandoah Valley, before I-81 was built.)  The middle sign directs US 17, US 50, and US 522 traffic to the left, onto Gerrard.  Signage heading east on Gerrard once looked like this:

Now westbound US 50 traffic is directed to turn west on Cork Street (instead of Picadilly), and approaching that intersection an "End" assembly is posted for US 17: