Elections are costly. Candidates, especially those running for president, have to consider how to pay for staff salaries, speaking venues, travel, food, and state election fees, among other things. Fundraising, then, becomes an integral part of political campaigns, and some areas of the country are better equipped to contribute than others.

Campaign donations are broken into two categories: itemized and unitemized contributions. All contributions between $200 and $2,700 — the contribution limit to a single candidate — must be itemized, which entails disclosing to the Federal Election Commission (FEC) the amount, donor’s name, zip code, occupation, and donor’s employer. Donations below $200 are not required to be itemized — although some are. Based on FEC campaign finance data from the beginning of each candidate’s campaign through February, these are the zip codes contributing the most to Republican presidential candidates.

While an unitemized donation is necessarily smaller than an itemized donation, unitemized donations still represent a significant share of a candidate’s fundraising efforts. Unitemized contributions to Sen. Ted Cruz’s campaign, for example, account for 41.7% of the $66.2 million raised from individuals. Donald Trump, on the other hand, who is largely financing his own campaign, does not need to court donors in the same way. Just one-quarter of the $9.5 million raised by his campaign is from itemized donations.

Click here to see the 8 neighborhoods contributing more than $500,000 to Republican Candidates.

Areas in a candidate’s home state are often home to the largest donors. Of the eight zip codes in the country donating more than $500,000 to Republican candidates for president, five are located in Texas, the home state of Sen. Cruz and a state with strong familial ties to former Florida Gov. Jeb Bush. Cruz led GOP fundraising efforts in the Texas zip codes, raising a combined $2.2 million.

Additionally, many zip codes donating the most money did so early in a candidate’s campaign, a sign of a well established financial apparatus as well as a signal of strong initial support. Indeed, Cruz raised nearly half of the money in the 77024 zip code of Houston in the four months after he announced his bid for the Republican nomination.

While these zip codes have each donated more than $500,000 to Republican presidential candidates, political contributions from these areas are not exclusive to the GOP. In fact, the two zip codes donating the most to Republicans located in New York City — 10022 and 10065 — have donated far more to former Secretary of State Hillary Clinton’s campaign than any Republican candidate.

Unsurprisingly, individuals donating the most to presidential candidates live in affluent areas. In five of the eight zip codes contributing more than $500,000 to Republican candidates, the median annual household income is greater than $110,000, more than double the U.S. figure. The median household income in Houston’s 75225 zip code is $156,173 a year. At least $700,000 has been raised so far from that zip code.

Successful fundraising does not necessarily translate to popular support, however. Former Florida Governor Jeb Bush, for example, raised more than $33.5 million through private contributions, yet suspended his campaign after disappointing finishes in Iowa, New Hampshire, and South Carolina. Donald Trump, the Republican frontrunner, on the other hand, has raised just $9.5 million through February.

To determine the zip codes donating more than $500,000 to Republican presidential hopefuls, 24/7 Wall St. looked at itemized contributions reported to the FEC by each candidate’s campaign as of the March 2016 filing period. Additionally, we considered median household income and educational attainment rates from the U.S. Census Bureau’s 2014 American Community Survey (ACS).

These are the eight zip codes donating more than $500,000 to Republican candidates.

8. Zip code: 10022
Area: Midtown East
City: New York, NY
Contributions to Republicans: $541,423

More than $540,000 in donations to Republican presidential candidates came from the 10022 zip code, which covers Midtown East in Manhattan, near the Museum of Modern Art and Rockefeller Center. Bush received nearly 40% of donations from this area. Sen. Marco Rubio of Florida raised roughly $128,000 in the area, or 23.6% of all donations coming from this zip code. While the area’s contributions to Republican candidates was the eighth highest of any U.S. zip code, the area’s contributions to Democratic presidential candidates were far higher. Through February, Clinton’s campaign had raised more from this area than all Republican presidential candidates combined. Other Democrats also found success in the zip code, with Sen. Bernie Sanders of Vermont, former Maryland Gov. Martin O’Malley, and Sen. Jim Webb of Virginia all receiving donations. Together, this zip code contributed $632,066 to Democratic candidates.

7. Zip code: 10065
Area: Lenox Hill
City: New York, NY
Contributions to Republicans: $560,629

Located near Lenox Hill on the east side of Manhattan between the Upper East Side and Midtown, the 10065 zip code contributed roughly $561,000 to 2016 Republican presidential hopefuls, the seventh highest amount of all U.S. zip codes. As in other areas of New York, Bush received the lion’s share of donations from this area, with roughly 120 individual contributions totalling $238,000. New Jersey Gov. Chris Christie also did well in this area, receiving $57,700 in total donations. On the Democratic side, Clinton received nearly $500,000 in donations from this zip code.

6. Zip code: 75225
Area: N/A
City: Dallas, TX
Contributions to Republicans: $707,879

Through February, itemized contributions from the 75225 zip code in northern Dallas to Republican presidential hopefuls totalled $707,879. As with other areas of Texas, Cruz led fundraising efforts in this zip code, raising nearly $225,000. Despite receiving the largest sum, support for Cruz was not necessarily universal. In fact, every Republican candidate except former Louisiana Gov. Bobby Jindal received money from residents in this area. Former Texas Gov. Rick Perry, retired neurosurgeon Ben Carson, Bush, Christie, and Rubio each received at least $25,000 in itemized donations from this area.

5. Zip code: 75205
Area: Highland Park
City: Dallas, TX
Contributions to Republicans: $759,931

The 75205 zip code is located in Highland Park, an affluent area of Dallas, Texas. Collectively, residents donated $759,931 to Republican presidential hopefuls through February. Unlike other zip codes contributing large sums of money to presidential campaigns, donations from this area were well distributed among Republican candidates. Cruz, Rubio, and Bush each received more than $130,000 in donations from this area. In addition, Carson, Christie, and former Hewlett-Packard CEO Carly Fiorina also received sizable donations.

4. Zip code: 77056
Area: Galleria
City: Houston, TX
Contributions to Republicans: $800,204

Houston native Cruz received the most donations from the 77056 zip code to the west of the city. As much as 55.1% of the $800,204 raised by Republican presidential candidates through February in this area went to his campaign. Bush and Rubio also received sizable donations from this area. Large campaign contributions may be due in part to higher educational attainment, which can lead to higher incomes. Nearly 74% of adults in the this zip code have a bachelor’s degree, roughly three times the state attainment rate of 27.1%. Additionally, the area’s median household income is $92,521, far higher than the $52,576 statewide figure.

3. Zip code: 77019
Area: River Oaks
City: Houston, TX
Contributions to Republicans: $803,074

Located near downtown Houston, residents of the 77019 zip code donated $803,074 in itemized contributions to Republican candidates for president in 2016, the third highest sum of any zip code in the country. As with other areas in Houston, Cruz garnered the most financial support from this zip code, raising more than $396,000 through February. Bush’s family connections in Texas likely aided his efforts to raise nearly $194,000 in this zip code, the second largest fundraising effort in the area.

2. Zip code: 33480
Area: N/A
City: Palm Beach, FL
Contributions to Republicans: $842,502

Located in the home state of two former Republican presidential nominee seekers — Bush and Rubio — the 33480 zip code of Palm Beach, Florida was a major contributor to those candidates’ campaigns. While Bush and Rubio suspended their presidential campaigns, they each raised more than $200,000 in this area. Cruz and Kasich, both still in contention for their party’s nomination, raised $139,000 and $100,000, respectively. All told, area residents have donated $842,502 to Republican presidential candidates through February.

1. Zip code: 77024
Area: The Villages
City: Houston, TX
Contributions to Republicans: $1,592,706

With itemized donations totalling nearly $1.6 million, the 77024 zip code of western Houston is by far the most lucrative zip code in the country for Republican candidates for president. As in other areas of Texas, Cruz led fundraising efforts, raising $915,953 since his campaign started in March 2015. Other candidates’ fundraising efforts in this area were also successful. Bush, Rubio, and Carson each raised at least $90,000.

Thank you for reading! Have some feedback for us?
Contact the 24/7 Wall St. editorial team.