[2] The county was created by an act of the Congress of the Republic of Texas on December 14, 1837, and is named for the town of Montgomery.

[14] In 2004, county voters gave 78.1 percent of their vote to Republican candidate George W.

[15] In 2008, 75.8% of the voters supported the Republican ticket of John McCain and Sarah Palin.

[16] In 2016, Montgomery County was the only county in the United States where Republican nominee Donald Trump won against Democratic nominee Hillary Clinton by a margin of greater than 100,000 votes.

[17] In 2020, Trump won Montgomery County again, with an expanded margin of 119,000 votes.

[18] In 2024, Trump won Montgomery County once again, with another expanded margin of about 140,000 votes.

Lone Star College's service area under Texas law includes, in Montgomery County: Conroe, Magnolia, Montgomery, New Caney, Splendora, Tomball, and Willis ISDs.

The portion in Richards ISD is zoned to Blinn Junior College District.

One toll road consists of a section of mainlanes of State Highway 249 between the Harris County line at Spring Creek to FM 1774 in Pinehurst and is signed as MCTRA 249 Tollway (maintained by the Montgomery County Toll Road Authority).

[29] North of Pinehurst, the toll road continues as the TxDOT maintained Aggie Expressway (SH 249 Toll) up north to FM 1774 near Todd Mission then as a two-lane freeway up to State Highway 105 near Navasota.