Columbia subject headings:
Immigrants--United States--History--Congresses.
Ports of entry--United States--History--Congresses.
United States--Emigration and immigration--History--Congresses.
Harvard subject headings:
Immigrants--United States--History--Congresses.
Ports of entry--United States--History--Congresses.
United States--Emigration and immigration--History--Congresses.
Princeton subject headings:
Immigrants--United States--History--Congresses.
Ports of entry--United States--History--Congresses.
United States--Emigration and immigration--History--Congresses.