If you have any people from Monroe County that you think might have served in the first World War then you definitely should look at the 3 volume set; World War Service Record of Rochester and Monroe County, N.Y. These 3 volumes were compiled by Edward R. Foreman, who was the Rochester City Historian at that time.
Volume one (1924) of the series is subtitled: Those Who Died for Us. It is a list of those from Monroe County that died during the war. Place of birth is listed and sometimes date of birth and parent’s names. Then is listed the military data, including where enlisted and unit served in and details of when and where the person died. The list is almost 100% men but just leafing through the volume I did find one lady that was a nurse that died in the war. At the back of this volume is a series of pictures of at least (0% of those that died during the World War.
Volume two (1928) is subtitled: Those Who Went Forth to Serve and is almost 2000 pages with approximately 15,000 veterans. For most veterans, is listed their address in 1928, place of birth and military data. That has enlistment, unit(s) served in and details of the discharge. This volume is usually where you want to start as there are so many veterans listed.
Volume three (1930) is subtitled: Those Who Supported the War and tells about those organizations that gave their support. There are the organizations that you would expect to find like the Red Cross, Draft Board and the War Chest. There also are some articles of local companies like Eastman Kodak (aerial photograph), Bausch & Lomb (range finders) and General Railway Signal (artillery shells). Then there are those organizations that you wouldn’t think about at first like the American Library Association that collected books for soldiers and even the Daughters of the American Revolution that collected food for European refuges. There is an index in this volume but it not an every name index.
Where can you find this series? Many libraries here in Monroe County have them. See the Monroe Co. Library System for exact locations. For other libraries in the US, do a search on Worldcat. The series occasionally appear on e-Bay and book seller sites but they are very expensive.