Can I claim right to property I have cared for 25 years?

"Claiming" the property is not a simple process.  You'd have to find and sue the owner to have that property transferred to you pursuant to the doctrine of adverse possession.   The analysis that goes into whether you can be successful is complex.  You'll have to incur quite a few costs, including litigation and maybe a survey to "slice off" what you claim from a larger parcel (if applicable).  Is it worth it?  Go into it with eyes wide open.