Congress created the United States Supreme Court in 1789 and divided the US into 13 "districts" and these districts were grouped in three circuits. In 1911 the circuit courts were abolished and the records were transferred to the distric courts.
In 1789 each state had one district court (13 states). However, due to population expansion, each state had several and started to divide into divisions. District courts handle maritime law, bankruptcy, criminal suits, civil cases and private land grant cases.
Circuit courts handled appeals from district courts, and civil and some criminal triable under federal statute.Some legal jurisdiction was shared by the federal courts, for instance, naturalizations could take place in a district or circuit court or the Supreme Court.
Genealogists are interested in the records of the courts such as docket books, minute books, and case files. Docket books are the agenda of the cases to be heard and can serve as an index. You can scan the docket for your surname then find the records in the appropriate place. Minute books is the log of the actions taken by the court. For every action pertaining to a case, the case number appears and by scanning the pages of the minute book for every occurrence of the case number you got from the docket book you can find the information you want. The Case file (or packet) contains all the papers filed in connection with the case.
If you come across a reference to a federal court order then you can retrieve the file. Send the information to the Regional Archives that hold the records for that court and request a photocopy of the file (for a modest fee). Write to the National Archives, Washington, DC 20408 for the addresses of the Regional Archives and the states they serve. Ask for Leaflet #22, it is free.
You may want to visit a cemetery to record the final resting place for several members of your family. More than likely, you will find more than several, probably hundreds appear to be people who are related to you. It might be a goldmine of information. If you have not brought enough paper, pencils, film for the camera, flashbulbs, etc. you will find yourself trying to abbreviate, write teeny tiny, leave off info you think you will remember, etc. You will forget, believe me! Much of the data you drove so far to get will be lost. Plan your trip with enough pencils (sharpened already) paper (for headstone tracings) extra film, extra batteries for camera and for laptop computer, and discs. Also plan enough time to accomplish all the things you want to do.