To find Supreme Court cases, use the appropriate set -- the source is abbreviated in the case citation. There is a table in the front of each volume of the Supreme Court Reporter (West Publishing) that can be used to convert a U.S. Reports citation to the appropriate Supreme Court Reporter citation.
A complete case citation provides the volume, source and page number.
For example: 100 U.S.124 indicates Volume 100 of the United States Reports, page 124.
If your citation abbreviation is "S.Ct."
the source is the Supreme Court Reporter (West Publishing)
Location: JPL 3rd Floor KF 101 .S9
the source is United States Reports: Cases adjudged in the Supreme Court.
Location: JPL 3rd Floor KF 101 .U58