This is Quince Alley, which sits between South Water and South Front streets. The building on the right has been several different restaurants. This was shot from near Water Street and looking down the alley toward Front Street. The building in the background is still there with the same structure, which is what is shown on the map below:

This location serves as a conflict zone in which the boys all get serious with each other. Dinger (Corey Haim) and Derek (John Ward) show up to find Joel trying to exact lethal revenge on Dumas (Matt Adler) and his gang.

Dinger (Corey Haim) waits for Joel (William McNamara) to surprise him with his late night plans. This leads to Joel flying solo and seeking out the other mean boys to give them a talkin’ to.

Only seen once, this house is not yet located, but since so much of the locations are right nearby each other, I’ll probably find it. But if you are reading this, I probably gave up. So much for 100% location coverage.