Marion County
Indiana · County seat: Indianapolis · County equivalent (e.g. borough in AK, parish in LA)
FIPS code 18097 is Marion County, Indiana. With a population of 971,737 (2022 ACS estimate), it ranks #1 in Indiana and #51 nationally. Marion County is part of the Indianapolis-Carmel-Greenwood, IN. The state FIPS code for Indiana is 18. This code is used in Census Bureau, BLS, EPA, HUD, and USDA federal datasets to identify this county.
County FIPS
18097
Population
971,737
2022 ACS · #51 nationally
Density
2,452.0/mi²
people per sq mile
Land Area
396
sq miles
Urban/Rural
Metro — 1M+ population
RUCC 1
How This FIPS Code Works
The 5-digit FIPS code 18097 is formed by combining the 2-digit state identifier 18 (Indiana) with the 3-digit county identifier 097. Together they uniquely identify Marion County in every US federal dataset. No two counties share the same 5-digit FIPS code.
Census ACS Data for FIPS 18097
From the 2022 ACS 5-year estimates — the same values you'd retrieve by querying the Census API with county FIPS 18097.
Median Household Income
$59,504
ACS B19013_001E
Poverty Rate
15.4%
ACS B17001 (below poverty level)
Median Age
34.4
ACS B01002_001E
Metropolitan Area
Adjacent Counties (7)
Counties that share a border with Marion County. Useful for regional analysis — these are the geographies you'd typically include when studying labor markets, commuting zones, or environmental spillovers around FIPS 18097.
Federal Datasets Using Code 18097
FIPS code 18097 appears as the county identifier in the following federal datasets. Analysts joining data across these sources use this code as the common geographic key.
Using FIPS Code 18097 in Code
Common patterns for querying federal datasets by this county's FIPS code. The leading zeros are significant — always treat FIPS codes as strings, not integers.
import requests
url = "https://api.census.gov/data/2022/acs/acs5"
params = {
"get": "NAME,B19013_001E,B01003_001E",
"for": "county:097",
"in": "state:18",
"key": "YOUR_CENSUS_API_KEY",
}
r = requests.get(url, params=params)
data = r.json() # [[header...], [Marion County, Indiana, income, pop, ...]-- 5-digit combined FIPS (state + county)
SELECT * FROM your_table WHERE county_fips = '18097';
-- Some datasets store state and county separately
SELECT * FROM your_table
WHERE state_fips = '18'
AND county_fips = '097';
-- ⚠ Never cast to integer — leading zeros are lost:
-- county_fips = 18097 is WRONG for this countylibrary(tidycensus)
get_acs(
geography = "county",
variables = c(income = "B19013_001E", pop = "B01003_001E"),
state = "18",
county = "097",
year = 2022
)ZIP Codes in Marion County
ZIP codes do not align perfectly with county boundaries — a single ZIP code can span multiple counties, and a county can contain parts of many ZIP codes. The ratios below (from the Census 2020 ZCTA relationship file) show the land area share of each ZCTA that falls within Marion County. Why FIPS ≠ ZIP →
| ZIP Code | % in county |
|---|---|
| 46237 | 100.0% |
| 46107 | 100.0% |
| 46216 | 100.0% |
| 46217 | 100.0% |
| 46218 | 100.0% |
| 46219 | 100.0% |
| 46220 | 100.0% |
| 46221 | 100.0% |
| 46222 | 100.0% |
| 46224 | 100.0% |
| 46225 | 100.0% |
| 46226 | 100.0% |
| 46227 | 100.0% |
| 46228 | 100.0% |
| 46235 | 100.0% |
| 46241 | 100.0% |
| 46254 | 100.0% |
| 46183 | 100.0% |
| 46201 | 100.0% |
| 46202 | 100.0% |
| 46203 | 100.0% |
| 46204 | 100.0% |
| 46205 | 100.0% |
| 46206 | 100.0% |
| 46208 | 100.0% |
| 46214 | 100.0% |
| 46236 | 99.8% |
| 46250 | 99.4% |
| 46239 | 99.2% |
| 46260 | 99.0% |
Showing top 30 of 41 ZIP codes by residential address share.