Assuming you are using an iframe to import content available to the public but not owned by you into your website, you can always use the page anchor to direct you iframe to load where you want it to.
First you create an iframe with the width and height needed to display the data.
<iframe src="http://www.example.com/page2.html" width="200px" height="100px"></iframe>
Second install addon such as Show Anchors 2 for Firefox and use it to display all the page anchors on the page you would like display in your iframe. Find the anchor point you want your frame to use and copy the anchor location by right clicking on it.
(You can download and install the plugin here => https://addons.mozilla.org/en-us/firefox/addon/show-anchors-2/)
Third use the copied web address with anchor point as your iframe source. When the frame loads, it will show the page starting at the anchor point you specified.
<iframe src="http://www.example.com/page2.html#anchorname_1" width="200px" height="100px"></iframe>
That is the condensed instruction list.