Final answer:
The longest recess in the form of a government shutdown was between December 2018 and January 2019, making it the longest in U.S. history due to a disagreement over border wall funding.
Step-by-step explanation:
The longest recess that the United States Congress took, in terms of a government shutdown, occurred between December 2018 and January 2019.
This was primarily due to disagreements over funding for a border wall. While previous government shutdowns had happened, including those in the 1980s and more notable ones in December-January 1995-1996 and for two weeks in October 2013, the shutdown from December 2018 to January 2019 was the longest in U.S. history.
Hence, the most extended period of government shutdown, resulting from a disagreement over funding for a border wall, occurred from December 2018 to January 2019, marking the longest in U.S. history.