Hollon Parker was a petitioner in a case before the United States Supreme Court. The case involved a dispute between Parker and the State of Tennessee over the ownership of a tract of land. Parker claimed that he had purchased the land from the state in 1867, but the state argued that the sale was invalid because it had not been approved by the state legislature. The Supreme Court ruled in favor of Parker, finding that the sale was valid and that he was the rightful owner of the land. The Court held that the state had no authority to invalidate the sale, as it had been made in good faith and with the knowledge of the state. The Court also noted that the state had not taken any action to challenge the sale until after Parker had taken possession of the land. The Court's decision established that the state could not invalidate a sale that had been made in good faith and with the knowledge of the state. This ruling has been cited in numerous cases since, and has been used to protect the rights of individuals who have purchased land from the state.

In Hollon Parker v. United States, the Supreme Court was asked to decide whether a defendant who had been convicted of murder in the state court could be tried again for that same crime by the federal government. The majority opinion held that this double jeopardy did not apply because it only applied when two separate sovereigns were involved and since both trials were conducted under one sovereignty (the United States), there was no violation of double jeopardy protections. Justice Field dissented from this decision, arguing that although technically there may have been only one sovereign involved, each trial represented a distinct exercise of power by different branches within the government - namely, state and federal courts - which should be considered as separate sovereignties for purposes of applying double jeopardy principles. He argued further that allowing multiple prosecutions would lead to oppressive practices against defendants and undermine public confidence in our justice system.