Correlates of War Project datasets

Use in your agent

Load COW country codes into pandas and Parquet. Checked against the provider's documentation on Nov 1, 2026.

Access

• No account or key for the checked country-code CSV.
• Downloading accepts the project's citation, no-charge and no-redistribution terms.

Request

curl -O 'https://correlatesofwar.org/wp-content/uploads/COW-country-codes.csv'

Format

CSV rows with StateAbb, numeric CCode and StateNme columns for joining Correlates of War datasets.

Load into pandas and Parquet

Needs Python 3 with requests, pandas and pyarrow.

"""Correlates of War country codes -> pandas -> Parquet. No key."""
import io
import requests
import pandas as pd

URL = "https://correlatesofwar.org/wp-content/uploads/COW-country-codes.csv"
r = requests.get(URL, timeout=60)
r.raise_for_status()
df = pd.read_csv(io.BytesIO(r.content))
df.to_parquet("cow_country_codes.parquet", index=False)
print(len(df), "country codes", df.columns.tolist())

Run by us on 2026-11-01 (python 3.13.5 | pandas 3.1.0 | pyarrow 26.0.0 | requests 2.34.2). Result: 243 country codes ['StateAbb', 'CCode', 'StateNme']

Limits

• Rate limit: Not stated.
• Do not redistribute a dataset to a third party without written permission.
• Do not charge users for access to COW data.

Quirks

• The checked country-code CSV contains repeated identical rows, so deduplicate all three columns before treating it as a join table.
• Dataset versions have different end dates and coding rules; retain release identifiers and consult each codebook.
• Country identities and system membership change over time; a static name-to-code mapping is not a complete temporal crosswalk.

Terms and attribution

• Cite each dataset in the form requested on its individual page.
• Do not distribute datasets to third parties without written permission from the COW director and data host.
• Users cannot charge for access to COW data.

Sources

• https://correlatesofwar.org/data-sets/: “By downloading a COW dataset, you agree to the following terms and conditions:”
• https://correlatesofwar.org/data-sets/: “without written permission of the COW director and data host.”
• https://correlatesofwar.org/data-sets/state-system-membership/: “Version 2024 extends the temporal domain of the collection through December 2024.”
• https://correlatesofwar.org/data-sets/cow-country-codes-2/: “The list of states with COW abbreviations and ID numbers.”
• https://correlatesofwar.org/faq/: “COW data users cannot charge for access.”