From The National Parks Service:
From the 1880s into the 1960s, a majority of American states enforced segregation through "Jim Crow" laws (so called after a black character in minstrel shows). From Delaware to California, and from North Dakota to Texas, many states (and cities, too) could impose legal punishments on people for consorting with members of another race. The most common types of laws forbade intermarriage and ordered business owners and public institutions to keep their black and white clientele separated.
Here is a sample of laws from various states:

• Nurses: No person or corporation shall require any white female nurse to nurse in wards or rooms in hospitals, either public or private, in which Negro men are placed. (Alabama)
• Buses: All passenger stations in this state operated by any motor transportation company shall have separate waiting rooms or space and separate ticket windows for white and colored races. (Alabama)
• Railroads: The conductor of each passenger train is authorized and required to assign each passenger to the car or the division of the car, when it is divided by a partition, designated for the race to which such passenger belongs. (Alabama)
• Restaurants: It shall be unlawful to conduct a restaurant or other place for the serving of food in the city, at which white and colored people are served in the same room, unless such white and colored persons are effectively separated by a solid partition extending from the floor upward to a distance of seven feet or higher, and unless a separate entrance from the street is provided for each compartment.
• Pool and Billiard Rooms: It shall be unlawful for a Negro and white person to play together or in company with each other at any game of pool or billiards. (Alabama)
• Toilet Facilities, Male: Every employer of white or Negro males shall provide for such white or Negro males reasonably accessible and separate toilet facilities. (Alabama)
• Intermarriage: The marriage of a person of Caucasian blood with a Negro, Mongolian, Malay, or Hindu shall be null and void. (Arizona)
• Intermarriage: All marriages between a white person and a Negro person or between a white person and a person of Negro descent to the fourth generation inclusive, are hereby forever prohibited. (Florida)
• Cohabitation: Any Negro man and white women, or any white man and Negro woman, who are not married to each other, who shall habitually live in and occupy in the nighttime the same room shall each be punished by imprisonment not exceeding twelve (12) months, or by fine not exceeding five hundred ($500.00) dollars. (Florida)
• Education: The schools for white children and the schools for Negro children shall be conducted separately. (Florida)
• Juvenile Delinquents: There shall be separate buildings, not nearer than one fourth mile from each other, one for white boys and one for Negro boys. White boys and Negro boys shall not, in any manner, be associated together or worked together. (Florida)
• Mental Hospitals: The Board of Control shall see that proper and distinct apartments are arranged for said patients, so that in no case shall Negroes and white persons be together. (Georgia)
• Intermarriage: It shall be unlawful for a white person to marry anyone except a white person. Any marriage in violation of this section shall be void. (Georgia)
• Barbers: No colored barber shall serve as a barber [to] white women or girls. (Georgia)
• Burial: The officer in charge shall not bury, or allow to be buried, any colored persons upon ground set apart or used for the burial of white persons. (Georgia)
• Restaurants: All persons licensed to conduct a restaurant, shall serve either white people exclusively or colored people exclusively and shall not sell to the two races within the same room or serve the two races anywhere under the same license. (Georgia)
• Amateur Baseball: IT shall be unlawful for any amateur white baseball team to play baseball on any vacant lot or baseball diamond within two blocks of a playground devoted to the Negro race, and it shall be unlawful for any amateur colored baseball team to play baseball in any vacant lot or baseball diamond within two blocks of any playground devoted to the white race. (Georgia)
• Parks: It shall be unlawful for colored people to frequent any park owned or maintained by the city for the benefit, use and enjoyment of white persons. and unlawful for nay white person to frequent any park owned or maintained by the city for the use and benefit of colored persons. (Georgia)
• Wine and Beer: Any person licensed to conduct the business of selling beer or wine. shall serve either white people exclusively or colored people exclusively and shall not serve to the two races within the same room at any time. (Georgia)
• Reform Schools: The children of white and colored races committed to the houses of reform shall be kept entirely separate from each other. (Kentucky)
• Circus Tickets: All circuses, shows and tent exhibitions, to which the attendance of.more than one race is invited or expected to attend shall provide for the convenience of its patrons not less than two ticket offices with individual sellers, and not less than two entrances to the said performance, with individual ticket takers and receivers, and in the case of outside or tent performances, the said ticket offices shall not be less than twenty-five feet (25) apart. (Louisiana)
• Housing: Any person. who shall rent any part of any such building to a Negro person or a Negro family when such building is already in whole or in part in occupancy by a white person or white family, or vice versa when the building is in occupancy by a Negro person or Negro family, shall be guilty of a misdemeanor and on convictions thereof shall be punished by a fine of not less than twenty-five ($25) nor more than one hundred ($100.00) dollars or be imprisoned not less than 10, or more than 60 days, or both such fine and imprisonment in the discretion of the court. (Louisiana)
• The Blind: The board of trustees shall. maintain a separate building. on separate ground for the admission, care, instruction, and support of all blind persons of the colored or black race. (Louisiana)
• Intermarriage: All marriages between a white person and a Negro, or between a white person and a person of Negro descent, to the third generation, inclusive, or between a white person and a member of the Malay race; or between a person of Negro descent to the third Generation, inclusive, and a member of the Malay race, are forever prohibited, and shall be void. (Maryland)
• Education: Separate schools shall be maintained for the children of the white and colored races. (Mississippi)
• Promotion of Equality: Any person. who shall be guilty of printing, publishing or circulating printed, typewritten or written matter urging or presenting for public acceptance or general information, arguments or suggestions in favor of social equality or of intermarriage between whites and Negroes, shall be guilty of a misdemeanor and subject to fine or imprisonment not exceeding five hundred ($500.00) dollars or imprisonment not exceeding six (6) months or both. (Mississippi) Intermarriage: The marriage of a white person with a Negro or mulatto, or person who shall have one-eight or more of Negro blood shall be unlawful and void. (Mississippi)
• Hospital Entrances: There shall be maintained by the governing authorities of every hospital maintained by the state for the treatment of white and colored patients separate entrances for white and colored patients and visitors, and such entrances shall be used by the race only for which they are prepared. (Mississippi)
• Prisons: The warden shall see that the white convicts shall have separate apartments for both eating and sleeping from the Negro convicts. (Mississippi)
• Education: Separate free schools shall be established for the education of children of African descent; and it shall be unlawful for any colored child to attend any white school, or any white child to attend a colored school. (Missouri)
• Intermarriage: All marriages between . white persons and Negroes or white persons and Mongolians... are prohibited and declared absolutely void... . No person having one-eighth part or more of Negro blood shall be permitted to marry any white person, nor shall any white person be permitted to marry any Negro or person having one-eighth part or more of Negro blood. (Missouri)
• Education: Separate rooms [shall] be provided for the teaching of pupils of African descent, and [when] said rooms are so provided, such pupils may not be admitted to the school rooms occupied and used by pupils of Caucasian or other descent. (New Mexico)
• Textbooks: Books shall not be interchangeable between the white and colored schools, but shall be continued to be used by the race first using them. (North Carolina)
• Libraries: The state librarian is directed to fit up and maintain a separate place for the use of the colored people who may come to the library for the purpose of reading books or periodicals. (North Carolina)
• Militia: The white and colored militia shall be separately enrolled, and shall never be compelled to serve in the same organization. The organization of colored troops shall not be permitted where white troops are available, and colored troops shall be under the command of white officers. (North Carolina)
• Transportation: The. Utilities Commission. is empowered and directed to require the establishment of separate waiting rooms at all stations for the white and colored races. (North Carolina)
• Teaching: Any instructor who shall teach in any school, college or institution where members of the white and colored race are received and enrolled as pupils for instruction shall be deemed guilty of a misdemeanor, and upon conviction thereof, shall be fined in any sum not less than ten dollars ($10.00) not more than fifty dollars ($50.00) for each offense. (Oklahoma)
• Fishing, Boating, Bathing: The Conservation Commission shall have the right to make segregation of the white and colored races as to the exercise of rights of fishing, boating and bathing. (Oklahoma)
• Mining: The baths and lockers for the Negroes shall be separate from the white race, but may be in the same building. (Oklahoma)
• Telephone Booths: The Corporation Commission is hereby vested with power and authority to require telephone companies.. to maintain separate booths for white and colored patrons when there is a demand for such separate booths. That the Corporation Commission shall determine the necessity for said separate booths only upon complaint of the people in the town and vicinity to be served after due hearing as now provided by law in other complains filed with the Corporation Commission. (Oklahoma)
• Lunch Counters: No persons, firms, or corporations, who or which furnish meals to passengers at station restaurants or station eating houses, in times limited by common carriers of said passengers, shall furnish said meals to white and colored passengers in the same room, or at the same table , or at the same counter. (South Carolina)
• Child Custody: It shall be unlawful for any parent, relative, or other white person in this State, having the control or custody of any white child, by right or guardianship, natural or acquired, or otherwise, to dispose of, give or surrender such white child permanently into the custody, control, maintenance, or support of a Negro. (South Carolina)
• Libraries: Any white person of such county may use the county free libraries under the rules and regulations prescribed by the commissioners court and may be entitled to all the privileges thereof. Said court shall make proper provision for the Negroes of said county to be served through a separate branch or branches of the county free library, which shall be administered by a custodian of the Negro race under the supervision of the county librarian. (Texas)
• Education: The County Board of Education shall provide schools of two kinds: those for white children and those for colored children. (Texas)
• Theaters: Every person. operating. any public hall, theater, opera house, motion picture show or any place of public entertainment or public assemblage which is attended by both white and colored persons shall separate the white and colored race and shall set apart and designate. certain seats therein to be occupied by white persons and a portion thereof, or certain seats therein, to be occupied by colored persons. (Virginia)
• Railroads: The conductors or managers on all such railroads shall have power, and are hereby required, to assign to each white or colored passenger his or her respective car, coach, or compartment. If the passenger fails to disclose his race, the conductor and managers, acting in good faith shall be the sole judges of his race. (Virginia)
• Intermarriage: All marriages of white persons with Negroes, Mulattos, Mongolians, or Malaya hereafter contracted in the state of Wyoming are and shall be illegal and void. (Wyoming)