I have a house at Newport NH. I want to know where the property markers are. I cannot find them all.

Nobody online is going to be able to tell you where your property markers are.

Giving out your address online like that isn't a good idea either.

Go to the courthouse and get a plat of the property. Then start looking for corner markers, possibly rebar pins.

You may want to use a metal detector if you have not already.

Next when was the property surveyed, do you know there are markers ? For many what markers there were may long be gone.

Have you considered having it resurveyed, if there is a current issue ?