Because you overrode the default settings defined by the geometry package (such as \footskip) then the last settings will be applied to take effect. You set \footskip to 25pt and that is too small!
I recommend that you use geometry's settings only rather than mixing them with native length macros. The following native length macros should not be used if you have already loaded the geometry package.
\setlength{\headheight}{0.6in}
\setlength{\headsep}{25pt}
\setlength{\topmargin}{0pt}
\setlength{\footskip}{25pt}
\setlength{\marginparsep}{11pt}
The link How to avoid getting cropped marginpar? and the following code snippet may help you to understand how to set up the page layout.
\documentclass{article}
\usepackage
[
a4paper,% other options: a3paper, a5paper, etc
left=1cm,
right=2cm,
top=3cm,
bottom=4cm,
% use vmargin=2cm to make vertical margins equal to 2cm.
% us hmargin=3cm to make horizontal margins equal to 3cm.
% use margin=3cm to make all margins equal to 3cm.
]
{geometry}
\usepackage{lipsum}
\begin{document}
\lipsum[1]
\end{document}
If you need more, drop a comment.
I think the problem may well be that you've specified height=10in as one of the arguments of the geometry package; it should be height=11in, shouldn't it? (I noted you also specified width=8.5in.)
If so, it suffices to specify margin=1in as the argument for the geometry package and to specify letterpaper as an argument when the documentclass is specified.
Best Answer
You can use the
geometrypackage and write (I suppose you use biblatex, for instance):See §7 of the documentation ("Changing layout mid-document").