Columbia subject headings:
United States--History--1849-1877--Pictorial works.
United States--History--1865---Pictorial works.
Harvard subject headings:
Photography--United States--History
United States--History--1849-1877--Pictorial works.
United States--History--1865---Pictorial works.
Princeton subject headings:
United States--History--1849-1877--Pictorial works.
United States--History--1865---Pictorial works.