Adams |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 972 |
| Edwin J. Alexander | R | 698 |
| Kenneth C. Dorsett | R | 401 |
Asotin |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 1996 |
| Edwin J. Alexander | R | 764 |
| Kenneth C. Dorsett | R | 686 |
Benton |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 7568 |
| Edwin J. Alexander | R | 4184 |
| Kenneth C. Dorsett | R | 3300 |
Chelan |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 4531 |
| Edwin J. Alexander | R | 2772 |
| Kenneth C. Dorsett | R | 1674 |
Clallam |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 5109 |
| Edwin J. Alexander | R | 2525 |
| Kenneth C. Dorsett | R | 1112 |
Clark |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 10802 |
| Edwin J. Alexander | R | 6217 |
| Kenneth C. Dorsett | R | 2901 |
Columbia |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 671 |
| Edwin J. Alexander | R | 486 |
| Kenneth C. Dorsett | R | 234 |
Cowlitz |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 5095 |
| Edwin J. Alexander | R | 3228 |
| Kenneth C. Dorsett | R | 1477 |
Douglas |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 2342 |
| Edwin J. Alexander | R | 1026 |
| Kenneth C. Dorsett | R | 686 |
Ferry |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 461 |
| Edwin J. Alexander | R | 222 |
| Kenneth C. Dorsett | R | 117 |
Franklin |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 2369 |
| Edwin J. Alexander | R | 1186 |
| Kenneth C. Dorsett | R | 729 |
Garfield |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 531 |
| Edwin J. Alexander | R | 273 |
| Kenneth C. Dorsett | R | 219 |
Grant |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 5103 |
| Edwin J. Alexander | R | 1855 |
| Kenneth C. Dorsett | R | 1028 |
Grays Harbor |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 7287 |
| Edwin J. Alexander | R | 3969 |
| Kenneth C. Dorsett | R | 1164 |
Island |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 2067 |
| Edwin J. Alexander | R | 1527 |
| Kenneth C. Dorsett | R | 744 |
Jefferson |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 1565 |
| Edwin J. Alexander | R | 694 |
| Kenneth C. Dorsett | R | 317 |
King |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 87503 |
| Edwin J. Alexander | R | 58102 |
| Kenneth C. Dorsett | R | 37535 |
Kitsap |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 15086 |
| Edwin J. Alexander | R | 5267 |
| Kenneth C. Dorsett | R | 3076 |
Kittitas |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 2608 |
| Edwin J. Alexander | R | 1168 |
| Kenneth C. Dorsett | R | 669 |
Klickitat |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 1705 |
| Edwin J. Alexander | R | 941 |
| Kenneth C. Dorsett | R | 409 |
Lewis |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 5343 |
| Edwin J. Alexander | R | 3861 |
| Kenneth C. Dorsett | R | 1195 |
Lincoln |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 1366 |
| Edwin J. Alexander | R | 965 |
| Kenneth C. Dorsett | R | 500 |
Mason |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 3384 |
| Edwin J. Alexander | R | 1633 |
| Kenneth C. Dorsett | R | 592 |
Okanogan |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 3476 |
| Edwin J. Alexander | R | 1562 |
| Kenneth C. Dorsett | R | 943 |
Pacific |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 2378 |
| Edwin J. Alexander | R | 985 |
| Kenneth C. Dorsett | R | 329 |
Pend Oreille |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 934 |
| Edwin J. Alexander | R | 398 |
| Kenneth C. Dorsett | R | 279 |
Pierce |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 37194 |
| Edwin J. Alexander | R | 18073 |
| Kenneth C. Dorsett | R | 8543 |
San Juan |
| Candidate | Party | Votes |
|---|
| Edwin J. Alexander | R | 550 |
| Robert S. O'Brian | D | 488 |
| Kenneth C. Dorsett | R | 232 |
Skagit |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 6819 |
| Edwin J. Alexander | R | 3998 |
| Kenneth C. Dorsett | R | 1857 |
Skamania |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 950 |
| Edwin J. Alexander | R | 380 |
| Kenneth C. Dorsett | R | 205 |
Snohomish |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 22976 |
| Edwin J. Alexander | R | 12019 |
| Kenneth C. Dorsett | R | 6494 |
Spokane |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 24336 |
| Edwin J. Alexander | R | 16462 |
| Kenneth C. Dorsett | R | 10180 |
Stevens |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 2279 |
| Edwin J. Alexander | R | 1183 |
| Kenneth C. Dorsett | R | 854 |
Thurston |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 9196 |
| Edwin J. Alexander | R | 6756 |
| Kenneth C. Dorsett | R | 1435 |
Wahkiakum |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 565 |
| Edwin J. Alexander | R | 308 |
| Kenneth C. Dorsett | R | 101 |
Walla Walla |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 3036 |
| Edwin J. Alexander | R | 2414 |
| Kenneth C. Dorsett | R | 1345 |
Whatcom |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 7258 |
| Edwin J. Alexander | R | 5011 |
| Kenneth C. Dorsett | R | 1804 |
Whitman |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 2833 |
| Edwin J. Alexander | R | 2154 |
| Kenneth C. Dorsett | R | 1335 |
Yakima |
| Candidate | Party | Votes |
|---|
| Robert S. O'Brian | D | 9915 |
| Edwin J. Alexander | R | 7915 |
| Kenneth C. Dorsett | R | 4352 |