> In the modern US, most land boundaries aren't super important anymore. This depends enormously on density, lot size, and land value. My town has recently up

> In the modern US, most land boundaries aren't super important anymore. This depends enormously on density, lot size, and land value. My town has recently updated zoning to allow the construction of accessory dwelling units ("backyard cottages"), but whether a specific lot has a room for one often comes down to less than a foot. They are definitely going to require you to bring out a surveyor before you can get a construction permit.