From their website:
During the American Civil War (1861-1865), Indiana Governor Oliver P. Morton's staff recorded thousands of the governor's incoming and outgoing telegrams in small, bound books. The governor and his staff communicated by telegraph with President Lincoln, Cabinet members, U. S. Senators and Representatives, other Northern state governors, and generals commanding in all the theaters of operations. These volumes may be the best documentation of an important Northern governor during the Civil War to survive. The physical books are located at the Indiana State Archives, which collaborated with IUPUI University Library to make this digitization project possible.
Uses of the Telegraph Books
Researchers will find many uses of these messages. Biographers, local historians, and genealogists will all learn much from consulting these records.
You may also wish to examine their online collection of 14 digitized Indianapolis city directories: