Look at where I grew up. Har-Brack was Harrison Township and Brackenridge together and they produced three players in the ‘50s that made it into professional football:
Cookie Gilchrist – Member of the All-Time AFL team, 4x AFL All-Star, Buffalo Bills Wall of Fame, AFL’s first 1,000-yard rusher, led the AFL in rushing twice, AFL MVP 1962, set single game rushing record with 243 yards against the NY Jets
Dick Modzelewski – 2x All-American at Maryland, Outland trophy winner, CFB HOF member, set NFL record with 180 consecutive games played
Ed Modzelewski – All-American at Maryland, Sugar Bowl MVP, 1st round draft pick of the Steelers and sixth overall pick in the NFL draft.
In the '60s, the district has expanded to become Highlands adding Fawn Township and Tarentum and thus you have a larger population to draw from for athletics. Since then, if I’m not mistaken the only player to do anything of significance at the Division-I level has been Matt Bonislawski at UConn and he played quarterback when they moved their football program to Division I. There is a kid now at Highlands that’s walking-on to play at Penn State this coming year but other than that, I don't know of anyone else.
They became a bigger school district with a larger enrollment, and no one has come close to reaching the NFL let alone do much at the Division I level.
