Can I copy layers from one map to another?

[BrianHosken]

I made a copy of a map and added layers.  Now I want to put those layers onto the original map.  How can I do that?  Or, can i somehow merge the 2 maps into one?

[T__WayneWhitley]

Probably the easiest solution is, with both maps open, drag and drop layers from the TOC from the source map (the one you want to copy from) to the destination map (the one you want to copy to).  You can also right-click and copy/paste if that is more comfortable.  ...and cannot forget, if you have made layer files already outside the mxd, you could simply load from there.

[BrianHosken]

I just started using ArcGIS.  How do i open 2 maps at the same time?  In 2 different I.E. tabs?  Also, what is the TOC of the source map?

[MarkFawkes]

I just started using ArcGIS.  How do i open 2 maps at the same time?  In 2 different I.E. tabs?  Also, what is the TOC of the source map?

From your reference to "..I.E. tabs..." do you have two web based maps or are you using ArcGIS with maps saved as MXD files?

If ArcGIS, you can open two instances of Arc and have each of the maps displayed in a separate instance. The TOC is the table of contents - this is the list of layers showing on the map that is normally displayed on the left side of the map.