"You have been given some good replies. Here's another on how to do it

yourself:
If, between properties, at the street there is something like an
electric box or telephone box or something similar that belongs to the
government or utility, it is common the object is place exactly between

properties, with the center of the back of the box being a foot or less

outside the corner boundry.
If, between properties, at the back, there are already fences for the
homes behind you and beside you, it is likely the intersection of those

is very close to the corner boundry. If there is just one fence for
one house, it is likely the corner of that fence is just inside the
corner boundry.
Of course, you could have what I used to: a telephone box three feet
from a cable box in the front. Or the guy who put up the fence behind
you may not have gotten the corner right. But, unless you and your
neighbor are fighting over literally one or two feet, you probably
won't be far off. "

Wow, what great advice. The property boundery might be where the
utility chose to put a box. Or it might be where someone erected a
fence. But then again it might not, but you "probably" won't be far
off. Are you for real?

A surveyor for a typical house lot in a developed area will charge $500
bucks or so to come out and mark the corners. That way you will know
for sure. Other than that, you're just guessing. If there is
disagreement with a neigbor, as somone already suggested, I would ask
them if they have a survey or had the property marked recently. If
not, perhaps you could get both properties done for a better deal,
since part of the work overlaps.