Adams |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 2013 |
| Robert S. O'Brien | D | 1871 |
Asotin |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 3115 |
| Edwin J. Alexander | R | 1780 |
Benton |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 15110 |
| Edwin J. Alexander | R | 11695 |
Chelan |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 8785 |
| Edwin J. Alexander | R | 7442 |
Clallam |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 8187 |
| Edwin J. Alexander | R | 4564 |
Clark |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 21887 |
| Edwin J. Alexander | R | 15297 |
Columbia |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 1080 |
| Robert S. O'Brien | D | 960 |
Cowlitz |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 12526 |
| Edwin J. Alexander | R | 9479 |
Douglas |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 3527 |
| Edwin J. Alexander | R | 2465 |
Ferry |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 828 |
| Edwin J. Alexander | R | 475 |
Franklin |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 5690 |
| Edwin J. Alexander | R | 3500 |
Garfield |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 701 |
| Robert S. O'Brien | D | 650 |
Grant |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 8938 |
| Edwin J. Alexander | R | 4951 |
Grays Harbor |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 13621 |
| Edwin J. Alexander | R | 7490 |
Island |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 3495 |
| Edwin J. Alexander | R | 3110 |
Jefferson |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 2584 |
| Edwin J. Alexander | R | 1588 |
King |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 231112 |
| Edwin J. Alexander | R | 183823 |
Kitsap |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 22473 |
| Edwin J. Alexander | R | 12907 |
Kittitas |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 4753 |
| Edwin J. Alexander | R | 3101 |
Klickitat |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 2816 |
| Edwin J. Alexander | R | 2048 |
Lewis |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 9494 |
| Edwin J. Alexander | R | 8093 |
Lincoln |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 2675 |
| Robert S. O'Brien | D | 2197 |
Mason |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 4757 |
| Edwin J. Alexander | R | 2844 |
Okanogan |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 5785 |
| Edwin J. Alexander | R | 3805 |
Pacific |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 4062 |
| Edwin J. Alexander | R | 2129 |
Pend Oreille |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 1736 |
| Edwin J. Alexander | R | 991 |
Pierce |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 70781 |
| Edwin J. Alexander | R | 44285 |
San Juan |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 892 |
| Robert S. O'Brien | D | 700 |
Skagit |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 12231 |
| Edwin J. Alexander | R | 8607 |
Skamania |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 1368 |
| Edwin J. Alexander | R | 763 |
Snohomish |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 47288 |
| Edwin J. Alexander | R | 29173 |
Spokane |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 55423 |
| Edwin J. Alexander | R | 48827 |
Stevens |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 3727 |
| Edwin J. Alexander | R | 3206 |
Thurston |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 14016 |
| Edwin J. Alexander | R | 11842 |
Wahkiakum |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 816 |
| Edwin J. Alexander | R | 626 |
Walla Walla |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 8810 |
| Robert S. O'Brien | D | 7598 |
Whatcom |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 16097 |
| Edwin J. Alexander | R | 12204 |
Whitman |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 6762 |
| Robert S. O'Brien | D | 5532 |
Yakima |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brien | D | 26627 |
| Edwin J. Alexander | R | 21606 |