1966 United States House of Representatives elections

President Lyndon Johnson's coalition of big businessmen, trade unions, liberal intellectuals, white ethnic minorities, and blacks began to disintegrate before the 1966 election. Trade unions did not do as well as corporations during the Johnson years. Social welfare did poorly because Americans preferred reduction in taxes to social improvements. The Great Society was further weakened by reactions against urban violence (by white ethnics) and against the Vietnam War (by intellectuals and students).[1] Republicans campaigned on law and order concerns stemming from urban riots, Johnson's conduct of the Vietnam War, and on the sluggish economy, warning of looming inflation and growing federal deficits.[2]

The losses hit the Democratic Party's liberal wing hardest, which in turn decreased Johnson's ability to push his agenda through Congress.[3] The elections also helped the Republicans rehabilitate their image after their disastrous 1964 campaign.[4]

• Alaska's at-large congressional district: four-term Democratic incumbent Ralph Julian Rivers was defeated by Republican State Senator Howard Wallace Pollock.
• Arizona's 3rd congressional district: sophomore Democrat George F. Senner Jr. was defeated by state legislator Sam Steiger.
• Arkansas's 3rd congressional district: lumber executive and Arkansas GOP chair John Paul Hammerschmidt defeated incumbent James William Trimble, becoming the first Republican member of Arkansas' congressional delegation since Reconstruction.
• California's 18th congressional district: onetime Olympic gold medalist Robert B. Mathias defeated seven-term Democratic incumbent Harlan Hagen.
• California's 25th congressional district: Charles E. Wiggins defeated incumbent Democrat Ronald B. Cameron.
• California's 33rd congressional district: Jerry L. Pettis defeated incumbent Kenneth W. Dyal.
• Texas's 7th congressional district: businessman and 1964 U.S. Senate candidate George H. W. Bush defeated Democratic challenger Frank Briscoe for the seat vacated by John V. Dowdy (whose district had been renumbered the second).
• Texas's 18th congressional district: Bob Price succeeded retiring Democrat Walter Edward Rogers by defeating Dee Miller.

Elections are listed by date and district.

Parties		Seats				Popular Vote
		1964	1966	Change	Strength	Vote	%	Change
	Democratic Party	295	248	47	57.0%	26,934,136	50.9%	6.2%
	Republican Party	140	187	47	43.0%	25,521,157	48.2%	5.8%
	Conservative Party	-	-	-	-	208,756	0.4%	0.3%
	Independent	-	-	-	-	85,641	0.2%
	Liberal Party	-	-	-	-	75,303	0.1%	0.1%
	Peace and Freedom Party	-	-	-	-	16,922	<0.1%
	American Independent Party	-	-	-	-	14,461	<0.1%
	Constitution Party	-	-	-	-	11,110	<0.1%
	Socialist Labor Party	-	-	-	-	5,771	<0.1%
	Independent-Socialist Party	-	-	-	-	3,502	<0.1%
	New Hispano Party	-	-	-	-	2,263	<0.1%
	People's Choice Party	-	-	-	-	1,299	<0.1%
	Socialist Workers Party	-	-	-	-	1,014	<0.1%
	Veteran Party	-	-	-	-	939	<0.1%
	Others	-	-	-	-	29,701	0.1%	0.1%
Total		435	435	0	100.0%	52,901,975	100.0%	——

Source: Election Statistics - Office of the Clerk

¹ One vacancy due to refusal of House to seat Adam Clayton Powell Jr. (D-New York)

Florida redistricted to adjust for demographic changes; in addition to minor boundary changes a district was removed from northern Florida, and Broward County was broken out into its own district.[5]

Indiana redistricted for this election, election boundary changes forced two Republican incumbents into the same district while creating a new district that was won by another Republican.[5]

Maryland redistricted its at-large district into an 8th district around Montgomery County, managing to adjust boundaries so no existing incumbents were displaced.[5]