As far as I understand the Jim Crow laws did not refer to any single federal/national law, but rather the general government policy of providing "separate but equal" facilities to African Americans. The consequence of this policy was a series of local and state laws that segregated blacks in social life and institutions such as buses, schools, etc. The entirety of these local and state laws are referred to as "Jim Crow laws." The interesting part is that even though the federal government officially ended this policy in the late 1950s, state and local governments resisted and did not implement changes. They continued to segregate blacks and this stubborn discrimination eventually resulted in the Civil Rights movements across the US and most prominently in the South states.