We use a number of resources to determine what counties we have visited. If you know the roads you took on a particular trip, a good road atlas (such as those published by Rand McNally or AAA) is usually sufficient to determine which counties you passed through. But there are cases when the road atlas is inconclusive, and we have to resort to other means to find out if a particular road goes through a particular county.

Unlike most FAQ's, this one might not have answers to all the questions. If you are familiar enough with a particular section of road to definitively know the answer to one or more of these questions, please send us the answer. Or if you have a particular road/county question you can't resolve on your own, ask us and we'll add it to our list of unanswered questions.

Without further ado, here is a list of county/road combinations that are hard to know about from just looking at the road atlas.

1. Does US 63 go through Greene County? Yes. (TIGER map)
1. Does US 101 go through San Benito County?Yes.
1. Does I-70 go through Gilpin County?No.
1. Does I-295 enter Clay County?
2. Does US 19/98 go through Gilchrist County?Northbound only. (TIGER)
3. Does US 19 go through Lafayette County?No. (TIGER)
4. Does US 41 go through Monroe County? ???
1. Does I-75 go through Crawford County? Yes
2. Does I-85 enter Barrow County? Yes
3. Does I-85 enter Clayton County? Yes
4. Does I-85 go through Hall County? No (TIGER map)
5. Does I-85 enter Harris County? Yes
6. Does I-85 go through Hart County? Yes (TIGER map)+
7. Does US 23 enter Appling County? Yes (TIGER)
1. Does I-57 go through Clay County? Yes.
2. Does I-64 go through Hamilton County? No.
3. Does I-70 go through Jasper County? No.
4. Does I-80 go through Kendall County? ???
Westbound: probably
Eastbound: ??? (TIGER)
5. Does I-88 go through Ogle County? Yes.
6. Does I-294 go through DuPage County? No. But the off-ramp from southbound I-294 onto eastbound I-290 (Eisenhower Expy) does enter DuPage County.
1. Does I-64 go through Clark County? No.
2. Does I-64 go through DuBois County? Yes (TIGER map)
(Ferdinand is in Dubois County)
3. Does I-64 go through Gibson County?Yes (TIGER map)
4. Does I-65 pass through Hendricks County? Yes (TIGER map)
5. Does I-65 pass through Benton County? No.
6. Does I-65 go through Floyd County? No.
7. Does I-74 go through Rush County? Westbound, we think so. Eastbound, we're not sure.
1. Does US 20 (the pre-2003 alignment) go through Franklin County? Westbound only*
1. Does I-44 pass through Cherokee County? No.
2. Does I-70 pass through Lincoln County? Yes (TIGER)
3. ... Jefferson County? Nope (TIGER)
4. ... Johnson County? No (TIGER)
5. ... Pottowatomie County? No (TIGER)
6. ... Ottawa County? No (TIGER)
7. ... Logan County? Yes
8. Does US 56 pass though Seward County? Yes.
1. Does I-24 pass through Todd County? No (TIGER)
2. Does I-71 pass through Grant County? No.
3. Does I-75 pass through Clark County? No.
4. Does I-75 pass through Owen County? No.
5. Does the Western Kentucky Parkway go through Butler County? Yes (TIGER)
1. Does I-95 go through Waldo County? Yes.
1. Does I-75 pass through Emmet County? Yes.
2. Does I-75 pass through Gladwin County? No.
3. Does US 131 pass through Newaygo County? No.
1. Does I-35 pass through Caldwell County? Yes.
2. Does I-44 pass through Dallas County? No.
3. Does I-70 pass through Howard County? No (TIGER)
1. Does US 2 enter Red Lake County? Westbound only?
1. Does US 2 go through Garden County? No.
2. Does US 30 go through Nance County? No.
1. Does I-15 go through Lincoln County? No.
2. Does I-80 go through Storey County? Yes.
New Mexico
1. Does US 60 go through Valencia County? No
New York/Pennsylvania
1. Does NY 17 go through Bradford County, PA? Yes (TIGER)**
1. Does I-80/90 go through Ottawa County? Yes (twice, actually)
1. Does I-44 go through Wagoner County? Yes. (TIGER map)
2. Does US-62 go through Tillman County? ???
1. Does I-5 go through Yamhill County? In the enlarged view of Salem, OR, my Rand McNally Atlas says it does. No***
(also see New York)
1. Does I-70 enter Fayette County?Yes.
South Carolina
1. Does I-95 enter Beaufort County?No.
2. Does I-95 enter Darlington County?Yes.
3. Does I-95 enter Lee County?No.
4. Does I-95 enter Marlboro County?Yes.
1. Does I-24 pass through Franklin County?No.
2. Does I-65 pass through Sumner County? Yes (TIGER map)
1. Does I-20 enter Crane County? Yes
2. Does I-30 enter Collin County? No
3. Does I-40 go through Deaf Smith County? Yes
4. Does US 59 go through Rusk County? Yes
5. Does US 385 enter Crockett County? Yes
6. ... through Crane County? Yes
1. Does I-64 pass through Fluvanna County? Yes.
2. Does US 58 pass through Isle of Wight County? No.
3. Does US 58 pass through Sussex County? No.
West Virginia
1. Does I-79 pass through Gilmer County? Yes.
2. Does I-470 pass through Marshall County? No.

+ We think the TIGER database from the U.S. Census Bureau is pretty reliable, and they have a half-decent mapmaking server available for public use, so we'll include links to some TIGER maps that have an opinion or two about the above questions.

* Thanks to Jeff Morrison for this definitive answer:

On each side of the road on the segment in question is a rural street sign, one for Franklin (N side) and one for Hardin (S side). In the town of Ackley, which straddles the line, the county road junction is signed like this:
     Franklin               Hardin
       S56                   S56
     County                 County
The only difference is the county names.
Jeff also points out that US 20 passes through a "four corners" point at the intersection of Franklin, Butler, Grundy, and Hardin counties. Westbound travelers will go from Butler County into Franklin County, but eastbound travelers will go from Hardin County into Grundy County.

But even if you were eastbound, give yourself credit for Franklin County if you stopped to get gas on the left side of the highway. :-)

** NY 17 briefly crosses the Pennsylvania state line, becoming Pennsylvania State Hwy 17 for a moment, before returning to New York.

*** Your Rand McNally atlas is in error. The area depicted as Yamhill County in the expanded view of Portland should be Marion County. More recent versions of the Rand McNally atlas corrected this error.