Donors forked over hundreds of thousands of dollars in campaign contributions to candidates of both parties running for open seats on the Clark County Commission.

Three seats on the commission are up on the 2018 ballot, including those held by incumbent Jim Gibson and termed-out commissioners Susan Brager and Chris Giunchigliani.

Campaign finance reports published Tuesday indicate that the two open seats attracted significant contributions from donors, with at least four of the candidates raising more than six figures between January and May 2018.

Democratic state Sen. Tick Segerblom, running in the seat currently held by Giunchigliani, reported raising just over $264,000 over the five-month reporting period, and spending around $223,300.

His largest donations included:

• $15,000 combined from Republic Dumpco and Republic Environmental Technologies, Inc., entities formed by the county's garbage franchise
• $10,000 from Seashore Holdings, Inc., which is registered to prominent Las Vegas contractor Steve Menzies
• $10,000 from Nevada Restaurant Services Inc., which operates Dotty's
• $10,000 from Nevada Heart & Vascular, LLP
• $10,000 from Bilco Holdings LLC, which has the same address as Focus Plumbing
• $5,000 from Nevada Service Employees Union
• $5,000 from Sapphire Las Vegas, a strip club

Marco Hernandez, an organizer with Laborers Local 872, brought in more than $114,000 over the reporting period, and spent $53,000. He received $30,000 from properties affiliated with the Las Vegas Sands, chaired by Republican Party megadonor Sheldon Adelson and which usually does not donate in Democratic primaries, and $5,000 checks from Switch, the Las Vegas Metro Chamber of Commerce, South Point Hotel and Casino and the Las Vegas Police Protective Association.

He also received $5,000 from Sandstone PAC, which is registered with Clark County Commission chairman Steve Sisolak.

Because the commission district has such a large number of registered Democratic voters, whoever wins the primary will likely cruise in the general election. Republican candidates Trish Marsh and Randy Rose didn't report raising any funds throughout 2018.

But Republicans hoping to gain a seat on the commission, which is currently represented by all Democrats, can direct their hopes to attorney Tisha Black, running in the commission district being vacated by Brager. Black raised just over $250,000 during the reporting period, while spending about $146,000.

She took in $30,000 from properties affiliated with the Las Vegas Sands, and $10,000 contributions from a business affiliated with developer Nevada West Partners and from real estate development firm Picerne Development Corp.

Black outraised her likely general election opponent, former Democratic state Sen. Justin Jones. He reported raising $143,000 over the reporting period and spent just over $104,000, with major donations coming from Seashore Holdings, the Grand Sierra Resort in Reno and Service Employees International Union Local 1107.

Both Black and Jones are facing primary challenges from opponents who have largely self-funded their campaigns. Republican candidate Mitchell Tracey raised just over $16,000 over the reporting period, and Democratic hopeful Jason Hunt raised nearly $9,500.

Gibson, a Democrat who was appointed to the commission in June, reported raising just over $230,000 and spending around $149,000 over the reporting period. He received large contributions from the state's major gaming corporations, including $30,000 from Las Vegas Sands properties, $20,000 from MGM Resorts properties and $10,000 from Wynn Resorts.

Both of his prospective Republican opponents raised significantly less cash — former Clark County Republican Party chairwoman Cindy Lake raised around $6,700, and her primary opponent Fred Van Dover didn't report raising any funds. Libertarian candidate Doug Marsh loaned his campaign $4,000, but otherwise didn't report raising any funds.