An original state highway, NC 42 took a completely different route through Wake County when it first entered the county in 1938, although it's always been in the same general area. Its first routing was along modern Ten-Ten Road, with a short multiplex along NC 50 near the county line, to end at US 15A (now 401) at McCullers Crossroads halfway between Garner and Fuquay-Varina (which were two separate towns at that point). However, even though no map shows this, it's possible that 42 extended even further west along Ten-Ten, as far as Apex, given that the Ten-Ten Road exit from US 1 was signed as "Old NC 42" for many years.

In any case, 42 was completely rerouted in 1949. Instead of entering the county via Cleveland School Road the way it had for the previous eleven years, 42 was moved south on a new alignment to end at US 15A just outside Varina (the northern of the two towns; they merged in 1963). Ten years later, 42 was extended west through Varina and Fuquay Springs to travel west into Harnett County and eventually to Sanford.

No changes since 1959. It's still largely a two-lane country road, but with a good deal more traffic in the intervening time.

42 is, for the most part, the southernmost state/US highway in Wake County, with only the sections of US 401 and NC 55 south of Fuquay-Varina running south of the road. It hugs the southern county line for its entire existence in the county, never going more than 5 miles from the next county (either Johnston or Harnett).

The intersection at 42 and I-40, while in Johnston County, deserves some mention here.  When I-40 was completed through most of Johnston County in 1990, this was a simple diamond interchange that served very little traffic. Ten years later, the exit had more restaurants and shops that most exits along I-40 in Raleigh. Combine that with explosive residential growth in western Johnston County, and the area (known as Cleveland, though unincorporated and possessing Clayton addresses) is a daily traffic mess.