In Harry Potter and the Philosopher's Stone, the Dursleys were planning to send Dudley to Uncle Vernon's old school, Smeltings, in September. At the same time, they were also planning to send Harry to the local comprehensive school Stonewall High.
Quoting chapter 3:
When september came he would be going off to secondary school and, for the first time in his life, he wouldn't be with Dudley. […] Harry, on the other hand, was going to Stonewall High, the local comprehensive.
Also in chapter 4, Uncle Vernon says:
‘He's going to Stonewall High and he'll be grateful for it. […]’
We never get to see Stonewall High, because Harry goes to Hogwarts instead.
Is Stonewall High a boarding school such that Harry would spend most of his time there, coming home only for the vacations? Or was Harry to return to the Dursley's house every night instead?
This question came up when discussing the other question Why didn't the Dursleys gladly ship Harry off to Hogwarts?