No it's not.
The Satanist-Leninist poison vendors are chanting today that Afghanistan is the "longest war we've ever fought".
Nope. That's still Vietnam. We had troops there from 1959 to 1975, and significant numbers actively fighting from 1963 through 1975. The troop count before 1965 was not as large as our current contingent in Afghan, which may be why it's not considered to be a "war"; but I don't know how you can draw sharp lines in messy wars like these. In both cases we started with "unofficial" special ops guys for a while, then ramped up gradually to large numbers of regular fighters.