Paste your accounts, pick how many territories, and get them drawn on a colored map — geographically compact, evenly split. Free, no signup.
Geographic clustering: nearby accounts group together into compact zones, and the split is measured for evenness. Compact and even is what keeps drive time down and reps sane.
Here it is count-based. The =TERRITORY formula in the free InstaMaps add-on can balance by any column, revenue included.
A couple hundred works well. For bigger books, run it in Google Sheets with the add-on, where the whole column comes along.