For more than a century, the phrase “mainline Protestantism” has referred to a specific group of American Protestant denominations that held significant cultural, theological, and institutional influence. At the heart of this tradition stand the “Seven Sisters of Mainline Churches,” a term used by historians and sociologists to describe the seven most prominent, historically rooted, socially engaged, and ecumenically oriented Protestant bodies in the United States.

These denominations share roots in colonial-era Christianity, nineteenth-century institutional growth, twentieth-century ecumenical leadership, and ongoing debates over doctrine and social issues. But they have also undergone substantial transformation from their origins.

Below is a look at each of the Seven Sisters, their development, how they have changed, and how the broader concept of “mainline” came into being.

When Was the Term “Mainline” First Used?

The term “mainline Protestant” emerged in the early 20th century, but it was popularized between the 1920s and 1940s during the era of the Protestant establishment. It appears to derive partly from:

The Main Line suburbs of Philadelphia, associated with wealthy, old-stock Protestant families linked to churches like the Episcopalians and Presbyterians
Sociological writing in the mid-20th century describing “mainline” vs. “evangelical” Protestants
The idea of being in the cultural and denominational “main line” of American religion and public life

By the 1960s, the term was widely used in academic literature, and by the 1980s, sociologists regularly referred to the “Seven Sisters.”

What Makes a Denomination ‘Mainline’?

Mainline denominations share several characteristics:

1. Colonial or early American roots

Most trace their American identity to the 17th–19th centuries.

2. Historically dominant cultural influence

Mainline clergy and institutions shaped early American education, politics, reform movements, and social norms.

3. Ecumenical orientation

They were deeply involved in the World Council of Churches, National Council of Churches, and inter-denominational cooperation.

4. Moderately liberal theology

Historically aligned with:

Higher biblical criticism
Social gospel theology
Sacramental or liturgical reform
Acceptance of scientific developments
Progressive social stances (especially post-1950s)

5. National organizational structure

Strong central bodies, seminaries, and denominational agencies.

The Seven Sisters of Mainline Protestantism

1. United Methodist Church (UMC)

Origins:

Rooted in John Wesley’s Methodism in the 1700s
Organized in America as the Methodist Episcopal Church (1784)
Reunification in 1939 and again in the 1968 merger that created the UMC

Development & Change:

Shift from revivalist evangelical movement → structured, socially engaged denomination
Key player in the Social Gospel, temperance, abolitionism, and civil rights
Increasing theological diversity; debates on sexuality, ordination, and scriptural authority
In the 2020s, internal divisions led to splinter groups such as the Global Methodist Church

2. Evangelical Lutheran Church in America (ELCA)

Origins:

Formed through mergers of various German, Swedish, Norwegian, and Danish Lutheran bodies
Consolidated in 1988 as the ELCA

Development & Change:

Originally immigrant-specific and linguistically divided
Over time embraced English-language worship, liturgical renewal, and ecumenical relationships
Progressive doctrinal shifts on women’s ordination (1970) and LGBTQ clergy (2009)

3. Presbyterian Church (U.S.A.) – PC(USA)

Origins:

Rooted in Scottish and Ulster Presbyterianism brought to America in the 1600s
Multiple mergers and schisms (Old School vs. New School; Northern vs. Southern)
Modern structure formed in 1983 when northern and southern denominations reunited

Development & Change:

Historically influential in education and politics
Transition from Calvinist rigor → broader Reformed identity
Advocated social reforms through the 20th century
Increasing theological diversity, debates over ordination and sexuality

4. Episcopal Church (USA)

Origins:

American branch of the Church of England
Organized after the American Revolution in 1789

Development & Change:

Once the denomination of American elites, presidents, and founding families
Strong liturgical and sacramental tradition
Significant changes in the 20th century:
- Women’s ordination (1976)
- Prayer Book reform (1979)
- Acceptance of LGBTQ clergy (2000s)
Internal tensions led to breakaway Anglican bodies (ACNA, 2009)

5. American Baptist Churches USA (ABCUSA)

Origins:

Emerged from English Baptist immigrants in the 17th century
Name and national organization solidified in the 19th and early 20th centuries

Development & Change:

Historically linked to abolitionism, missionary movements, and religious liberty
Unlike more conservative Baptist groups, ABCUSA embraced higher criticism, ecumenism, and progressive social engagement
Maintains congregational autonomy, creating internal diversity on theology and ethical issues

6. United Church of Christ (UCC)

Origins:

Formed in 1957 from the merger of:
- Congregational Christian Churches
- Evangelical and Reformed Church
These older bodies trace ancestry to Puritans, German Reformed, and German Evangelical churches

Development & Change:

One of the most theologically liberal mainline denominations
Early leader in:
- Civil rights
- Women’s ordination
- LGBTQ inclusion (ordained first openly gay minister in 1972)
Strong emphasis on social justice, freedom of conscience, and progressive theology

7. Disciples of Christ (Christian Church)

Origins:

Emerged from the Stone-Campbell Restoration Movement in the early 1800s
Emphasized Christian unity, weekly communion, and congregational autonomy
Became a formal denomination in the early 20th century

Development & Change:

Shifted from frontier revivalism → ecumenical, socially progressive tradition
Embraced biblical criticism, civil rights activism, and inclusive ordination practices
Distinct from the more conservative Churches of Christ and independent Christian Churches

How Have the Seven Sisters Changed from Their Origins?

Across all seven, a pattern emerges:

From Evangelical or Confessional Roots → Toward Ecumenical, Progressive Protestantism

Many began with strong doctrinal boundaries, revivalism, or confessional identity
By the 20th century, they championed higher criticism, social reform, and openness to theological diversity

From Cultural Dominance → To Minority Status

Once the “establishment” of American religion (1880–1950)
Now represent a much smaller percentage due to secularization, demographic decline, and religious switching

From Uniform National Churches → To Diverse and Divided Bodies

Many schisms or realignments have developed (UMC, Episcopal Church, Presbyterians)
Debates often revolve around ordination, sexuality, and biblical authority

Other Denominations Often Considered “Mainline”

While the Seven Sisters are the core, other groups frequently included or adjacent to the mainline:

Denominations commonly added:

Moravian Church in America
Reformed Church in America (RCA)
Christian Reformed Church (CRC) (less often due to conservative theology)
Quakers (Religious Society of Friends)
Unitarian Universalists (historically Protestant, now post-Christian; included by some historians)

African American denominations historically linked to the mainline:

AME (African Methodist Episcopal Church)
AME Zion Church
Christian Methodist Episcopal Church

These historically Black churches share roots in the same early American Protestant traditions, though they developed independently because of racial segregation.

Conclusion

The “Seven Sisters of American Mainline Protestantism” represent a foundational layer of U.S. religious history. Their development mirrors the broader shifts in American culture—from colonial beginnings, through national expansion and reform movements, to modern debates over theology, ethics, and social change.

While their cultural influence has declined, their impact on American society, politics, and education remains unmistakable. And even as their membership shrinks, their commitment to ecumenism, social justice, and theological openness continues to shape American religious life.

Liked it? Take a second to support Stephen Bedard on Patreon!