I agree with the other comment and owning 5 - 10 acres in pa is not all that big a deal. A good realtor should be able to help you check on the requirements to build on the land.

Look into mineral rights. Many/most properties in pa do not come with mineral rights. Put very simplistically some company can show and mine/drill/strip your property for coal, limestone, oil, sand etc. Used to happen more often when coal mining was big. But good to know what you own if you in an area where this may happen. More here https://www.dep.pa.gov/Citizens/MSI/Pages/default.aspx

Also big part of pa has old mines under them and/or old oil gas wells or lines crossing them. Very much depends where in PA you are looking. See the official pa subsidence site for more info on mines and insurance https://www.dep.pa.gov/Citizens/MSI/Pages/default.aspx