Name Sites Samples
Wilson County 3 22
Wilson County 1 10
Wilson County 2 6
Windsor County 6 23
Winkler County 1 3
Winn Parish 1 1
Winona County 2 22
Winston County 1 3
Wise County 2 5
Wood County 13 33
Wood County 1 2
Woodward County 3 5
Wright County 1 2
Wyoming County 4 70
Wythe County 2 3
Yadkin County 2 7
Yalobusha County 2 6
Yazoo County 2 14
Yell County 2 4
Yellow Medicine County 1 4
York County 2 18
York County 1 9
Young County 1 41
Zapata County 5 53
Zavala County 10 37
Ziebach County 1 2
Ă…land Islands 1 6