Your local county zoning department will have info on restrictive lot zoning requirements. IE: SF zoned Single Family, MF: Mulit-Family, LC: Light Commercial...there should be a document that will show minimum lot size, square feet, etc...If you want to change it usually takes an appeal to a "change board", the community can petition against your appeal at a public hearing, 6 months - a year in most cases and fees. We have an online portal map that such zoning of lots, parcels, dimensioned lot lines, along with set-backs and easements.
The zoning department should also be able to provide CUPs (Conditional Use Permits) which could be discrepancies against the land the city requires fixing.
If it's a Tiny House there may be other private restrictions imposed by the ACC (Architectural Control Committees), Developers, covenant, land owners, such as minimum square feet. Most developments that are trying to maintain a uniform design are too large for most, other than finding a development of Tiny Homes...good luck with that. That leaves rural areas, mobile, modular home, RV parks, etc.