# Early professional soccer: sources and coverage

Reviewed September 12, 2026. Dataset: `lib/data/early-soccer-history.ts`.

This is a curated history of **covered outdoor leagues**, not a census of every
American professional soccer club. It supplements the MLS, USL and women's history
datasets. A year without a record means the archive has no covered club for that
year. It must never be described as a year without soccer.

## Membership coverage

| League | Seasons included | Team-seasons | Scope |
| --- | --- | ---: | --- |
| American Association of Professional Football (AAPF) | 1894 | 4 | All four clubs that actually entered play |
| American League of Professional Football (ALPF) | 1894 | 6 | All six clubs |
| United Soccer Association (USA) | 1967 | 12 | All local identities represented by overseas guest clubs |
| National Professional Soccer League (NPSL) | 1967 | 10 | All clubs in the unsanctioned professional league |
| Original North American Soccer League (NASL) | 1968–1984 | 254 | Every outdoor season, including Canadian franchises |

`status: complete` means club membership is complete **within that named league
and covered season range**. It does not mean venue history, every game, or all
American soccer is complete. The original ASL eras, regional professional leagues,
and the period between the original NASL and later histories still need research.
No memberships have been interpolated across those gaps.

## The first professional leagues

The [U.S. Soccer timeline](https://www.ussoccer.com/history/timeline) places an early
professional league attempt in 1894. More detailed newspaper research by Ed
Farnsworth for the Society for American Soccer History establishes that two rival
leagues existed. The AAPF began play on September 29, before the ALPF opened on
October 6. Use “the first professional leagues in 1894,” rather than claiming the
ALPF was unambiguously the first professional soccer in the country.

- [SASH: The AAPF and the ALPF](https://www.ussoccerhistory.org/the-aapf-and-the-alpf-the-beginnings-of-professional-league-soccer-in-the-united-states/) supplies actual AAPF participants, dates and grounds. Announced New York and Brooklyn AAPF teams never entered play and are excluded. AAPF players were paid while keeping other jobs. Earlier paid players are mentioned, without providing a sufficiently complete club/season inventory for the calculator.
- [American Soccer History Archives: ALPF](https://soccerhistoryusa.com/asha/alpf.html) supplies the six familiar club names. Its older attendance and match-total claims are not imported.
- [SASH: After the collapse](https://www.ussoccerhistory.org/after-the-collapse-alpf-vs-alpf-in-baltimore-and-fall-river-1894-96/) confirms Baltimore's Union Park home. Continued exhibitions and tours after the league folded are outside the league-season dataset.

The 1894 leagues receive `level: unclassified`. Modern division numbers should not
be applied retrospectively to them. NPSL 1967 also remains unclassified because it
was an unsanctioned professional rival. USA 1967 and the original NASL use the
top-flight category.

## 1894 locations

League membership and ground usage are sourced separately from coordinates. The
six ALPF points represent published locations of the historical ground sites.
They are not claims about surviving stadiums, entrances, precise pitch centers,
or geodetic survey accuracy. Philadelphia's 1894 ground is named Philadelphia
Baseball Park, not its later Baker Bowl name. Boston uses the site rebuilt in
1894. New York uses the 1891 onward Polo Grounds site, not the earlier locations.

| Club | Historical ground | Longitude, latitude | Coordinate reference |
| --- | --- | --- | --- |
| Baltimore Orioles | Union Park | -76.61278, 39.31806 | [Union Park](https://en.wikipedia.org/wiki/Union_Park_(Baltimore)) |
| Boston Beaneaters | South End Grounds | -71.08694, 42.33750 | [South End Grounds](https://en.wikipedia.org/wiki/South_End_Grounds) |
| Brooklyn Bridegrooms | Eastern Park | -73.90278, 40.67000 | [Eastern Park](https://en.wikipedia.org/wiki/Eastern_Park) |
| New York Giants | Polo Grounds | -73.93722, 40.83167 | [Polo Grounds](https://en.wikipedia.org/wiki/Polo_Grounds) |
| Philadelphia Phillies | Philadelphia Baseball Park | -75.15583, 39.99306 | [Ground site later known as Baker Bowl](https://en.wikipedia.org/wiki/Baker_Bowl) |
| Washington Senators | National Park / Boundary Field | -77.02028, 38.91750 | [Boundary Field](https://en.wikipedia.org/wiki/Boundary_Field) |

AAPF ground names are retained where documented, but the map points are rounded
city references and remain `precision: city`. Paterson's Haledon ground has not
been precisely geolocated. Newark-Kearny Unions are placed in Newark because their
covered home matches were at Cosmopolitan Park there.

## 1967–1984 membership and locations

The [RSSSF NASL archive](https://www.rsssf.org/usadave/nasl.html) compiles each
outdoor season's tables, with credits to David Whitney, David Litterer and Colin
Jose's *NASL: A Complete Record*. We import membership and identity facts, not
standings, attendance, player data or the narrative text. Indoor seasons, the
1969 International Cup's duplicate identities and post-NASL appearances in other
leagues are excluded. Relocations and renames are represented as distinct eras
with stable franchise IDs. The 1979 Atlanta Chiefs and 1981 Washington Diplomats
are distinct franchises from the earlier clubs with those names.

The archive occasionally abbreviates names or has inconsistent text. The 1978
Cosmos are named “Cosmos,” following the archive's note that “New York” returned in
1979 and [the club identity history](https://en.wikipedia.org/wiki/New_York_Cosmos_(1971%E2%80%931985)).
“St.Louis” is normalized to “St. Louis.” [Caribous of Colorado](https://funwhileitlasted.net/2012/06/30/1978-caribous-of-colorado/)
and [Las Vegas Quicksilvers](https://funwhileitlasted.net/2011/12/19/1977-las-vegas-quicksilvers/)
use the contemporary identities shown in the archived media guides.

NASL and 1967 locations are approximate city or metropolitan reference points,
rounded to two decimal places. **They are not historical stadium coordinates.**
The UI must display approximate distance and location labels for these records.
A known venue name does not upgrade a city point to venue precision.

Specific host-town corrections and source references:

- [New York Cosmos: Home Sweet Homes](https://www.nycosmos.com/news/2025/07/10/home-sweet-homes-the-cosmos-five-decade-journey-through-new-york-and-new-jersey/) supplies the club's own stadium chronology: primarily New York in 1971, Hofstra in Hempstead in 1972–73, Downing Stadium in 1974–75, Yankee Stadium in 1976, and Giants Stadium in East Rutherford from 1977. The 1971 and 1976 rows explicitly acknowledge additional grounds. One primary point cannot capture all match venues.
- [Hofstra Athletics](https://gohofstra.com/news/2012/9/25/ATH_Cosmos_Return_To_Roots_At_Hofstra) independently confirms 1972–73.
- [Connecticut Bicentennials](https://en.wikipedia.org/wiki/Connecticut_Bicentennials) documents the change from Hartford to New Haven for 1977.
- [New England Tea Men](https://en.wikipedia.org/wiki/New_England_Tea_Men) documents Foxborough, the intervening Boston season and the return to Foxborough.
- [Minnesota Kicks](https://en.wikipedia.org/wiki/Minnesota_Kicks) places the team's Metropolitan Stadium home in Bloomington.
- [California Surf](https://en.wikipedia.org/wiki/California_Surf) places the outdoor club in Anaheim.

## Verification

The authored ranges were expanded and compared with each of the 17 original NASL
outdoor membership tables. Every seasonal name matched after the explicit
normalizations above. Expected annual club counts are:

`1968:17, 1969:5, 1970:6, 1971:8, 1972:8, 1973:9, 1974:15, 1975:20, 1976:20, 1977:18, 1978:24, 1979:24, 1980:24, 1981:21, 1982:14, 1983:12, 1984:9`.

The initial file contains 105 era records, with no overlapping years for any
franchise ID. All 286 covered team-seasons have finite longitude/latitude values;
six have ground-site precision. More detailed venue research should replace
individual city records with supported season-specific coordinates while
preserving the membership and identity history.