M*A*S*H had 16 episodes in its final season, season 11.
The season aired on CBS from October 25, 1982, through February 28, 1983. It followed the fictional 4077th Mobile Army Surgical Hospital during the Korean War, even though the series itself ran for more than three times the length of that conflict.
Season 11 included regular half-hour episodes as well as the exceptionally long finale, “Goodbye, Farewell and Amen.” That finale is sometimes counted separately in discussions because its television running time was roughly two and a half hours, but it was still the concluding episode of season 11. Counting the season’s official episode list gives 16 episodes.
A common mix-up is confusing the number of episodes with the number of seasons: M*A*S*H ran for 11 seasons and 251 episodes overall. The final season also included major farewells for characters such as Charles Winchester, B.J. Hunnicutt, and Hawkeye Pierce.