McALLEN, Texas (Border Report) -- Former President Donald Trump won all of the South Texas border counties on Tuesday night, further proving that Republican voters are increasing in this once-Democratic stronghold region. Trump beat Democratic Vice President Kamala Harris in the eight counties bordering Mexico from the Gulf of Mexico to the eastern side of the Big Bend region -- a distance spanning over 400 miles. This includes the South Texas counties of Cameron, Hidalgo, Starr, Zapata, Webb, Maverick, Kinney and Val Verde. Former President Donald Trump won more votes in the 8 South Texas border counties on Tuesday. (Border Report graphic) Trump won Cameron County -- a traditionally Democratic stronghold -- by nearly 19,000 votes. He won more GOP-leaning Hidalgo County by over 6,300 votes, according to the Texas Secretary of State's office. Hidalgo County also re-elected Republican Congresswoman Monica De La Cruz to a second term on Tuesday night. GOP Congresswoman De La Cruz secures 2nd term Other border counties that Trump won in South Texas included: Val Verde County, which includes Del Rio, where Trump received 9,130 votes to 5,244 for Harris. Maverick County, which includes the border city of Eagle Pass, where Trump won 9,282 votes to 6,368 for Harris. Webb County, which includes the border city of Laredo, voted for Trump 33,374 over 31,934 for Harris. Zapata County, where Trump received 2,965 votes to 1,874 for Harris. Starr County where Trump received 9,443 votes to 6,845 for Harris. In 2020, tiny, rural Zapata County, located west of Starr County and with fewer than 14,000 residents, was the only county in the Rio Grande Valley that voted majority for Trump when he went against President Joe Biden. University of Texas Rio Grande Valley political science professor Andrew Smith says the numbers Tuesday night prove that the number of Republicans is increasing throughout this mostly Hispanic region, especially in the highly populated eastern border counties of Hidalgo and Cameron. "The margins for Democrats have been shrinking and shrinking in Hidalgo and even Cameron counties. No. 1 thanks to investments by Republicans in their ground game here, because of dissatisfaction with the Democratic Party on border security, social issues, and the economy," Smith told Border Report on Wednesday. Trump still brings jitters to leaders south of border The economy and inflation are hugely concerning in this region, Smith said,. The household income in the Rio Grande Valley is significantly lower than the nation median household income of $80,000. The median income in Hidalgo County in 2022 was $49,471, and in Cameron County was $47,435 in 2022, according to the Census Bureau. The other button issue in South Texas is immigration and migrants illegally crossing the border from Mexico. "With immigration being one of the top issues down here, and the perception -- rightly or wrongly -- that the Biden administration, including Harris, have not done enough to secure the border, I think inevitably led to this shift away from the Democratic Party, at least in terms of the presidential vote. And I think it's also reflected in the national trend of Hispanics, or at least Hispanic men, overwhelmingly of them going for Trump nationally," Smith said. Migrants are taken into custody by officials on Jan. 3, 2024, in Eagle Pass, Texas. (AP File Photo/Eric Gay) "Democrats have got to figure out a way to reach out to Hispanic voters. What happened here in the Valley is a microcosm of the national shift where Hispanics have started shifting away from the Democrats after 2018," Smith said. "Democrats are just going to have to figure out something." Sandra Sanchez can be reached at [email protected].