The application deadline is Feb 28. This includes 7th semester transcripts.
However, if you seek admission to West Point, waiting lowers your chances especially since USMA Admissions occasionally sends hints to highly qualified applicants indicative of interest quite early on in the process. Many candidates from last year and even more from prior years received their BFEs before February even began. That being said, if you turn in your last piece of what West Point calls the Admissions puzzle at the final possible minute, offers, LOAs, and even LOEs have gone out. Depending on how qualified you are, you may receive your offer later down the road in March or April...or May...or June...or not at all. There are some candidates that probably would have gotten into West Point if they didn't wait until the last minute, because as I said, some offers are distributed before the deadline...additionally, waiting makes it more difficult to get a waiver if you have any medical issues, which is something that is of utmost importance to your application process.
So instead of asking when the deadline is, set one for yourself. Mine was October 1st and I was all set before then with the exception of medical because I needed a waiver (like I said, these things take time)! So figure out what works well for you. Crank out the essays if they're not done. Get yourself to hurry-up-and-wait time!