Find Maximum Value in TH1D Within a Specific Region

like the title suggest, I wish to find the best way to find the maximum value in a histogram within a specific region (e.g. a plus minus 100 of a chosen bin).

So far, I have either
compared each entries for the region
set every other entries into 0 and use GetMaximum() (, which is most likely a bad idea in term of speed).

If there are better ways, I would really appreciated the help.
Thanks in advance.