The most expensive 2018 midterm campaigns

With the upcoming November elections determining which party will retain or gain control of the House and Senate, both Republican and Democrat congressional campaigns across the country are spending millions of dollars to win over voters.

Here are the five most expensive 2018 congressional races as measured by total spending, which includes candidate and outside spending, according to data sourced from the Federal Election Commission by the Center for Responsive Politics.

1. Florida Senate: 

More than $159 million has been spent so far in Florida, making it the most expensive race in this election cycle so far. Incumbent Democratic Sen. Bill Nelson's campaign has spent more than $25 million, while Republican challenger Gov. Rick Scott's campaign has spent more than $66 million.

2. Missouri Senate:

Campaign spending in the battleground state of Missouri has reached a whopping $108 million. Incumbent Democratic Sen. Claire McCaskill's campaign has spent nearly four times as much as Republican Josh Hawley's campaign has, at roughly $33 million and $7 million respectively.

3. Texas Senate:

Spending in the Texas senatorial race has increased dramatically, with Democrat Beto O'Rourke's campaign spending over $59 million, while incumbent Republican Sen. Ted Cruz's campaign has spent over $33 million.

4. Arizona Senate:

The battle for the late Republican Sen. John McCain's seat has become not only heated, but also pricey, with more than $95 million spent. Democrat Kyrsten Sinema's campaign has spent more than $19 million, while Republican Martha McSally has spent more than $13 million.

5. Indiana Senate:

More than $91 million has been spent in Indiana's dead-heat senatorial race so far, with Democrat incumbent Joe Donnelly's campaign spending more than $13 million, and Republican Mike Braun spending more than $14 million.