St. Tammany Parish, Louisiana

St. Tammany Parish is a parish in Louisiana, United States, on the north shore of Lake Pontchartrain across the Twin Span and Causeway bridges from New Orleans. It had a population of 264,570 at the 2020 census and covers 846 square miles (2,190 km2) of land centred near 30°24′N 89°58′W.

Covington is the parish seat, and its postal code is 70433. The parish has 3 cities, 3 towns, and several unincorporated communities and census-designated places, and sits in the Central time zone.

Towns & Villages in St. Tammany Parish

St. Tammany Parish has 6 incorporated municipalities and dozens of unincorporated communities and subdivisions, mostly clustered along US 190, US 90, and the I-12/I-59 corridors. The table below covers the incorporated places and the larger named communities; CDP = census-designated place, Unincorp. = unincorporated community.

The parish is dotted with dozens of small named subdivisions and rural crossroads — Bayou Liberty, Chinchuba, Bonfouca, Pine Crest, and similar names on the old parish rolls — that are residential subdivisions or platted communities rather than separately governed places; they are best located by their ZIP-code town above rather than listed individually.

ZIP Codes

• 70433 — Covington (also serves Goodbee, Fontainebleau)
• 70435 — Covington (PO box station)
• 70458 — Slidell
• 70460 — Slidell (also serves North Slidell)
• 70461 — Slidell (also serves Cross Gates)
• 70448 — Mandeville (also serves Eden Isle, Lewisburg, North Shore Beach)
• 70471 — Mandeville (PO box station)
• 70447 — Madisonville
• 70452 — Pearl River
• 70420 — Abita Springs
• 70437 — Folsom
• 70431 — Bush
• 70445 — Lacombe (also serves Big Branch)

Talisheek (70464), Sun (70463), and Saint Benedict (70457) are served by PO-box-only ZIP codes rather than home delivery.

Geography

St. Tammany Parish sits on Louisiana’s Florida Parishes north shore, bounded on the south by Lake Pontchartrain. The terrain rises gently from coastal marsh and bayou country in the south to piney, sandy uplands in the north, drained by the Tchefuncte, Bogue Falaya, and Pearl rivers. About a quarter of the parish’s total area is water.

The parish borders Washington Parish to the north, Pearl River County and Hancock County, Mississippi to the east, Orleans Parish and Lake Pontchartrain to the south, Jefferson Parish across the lake to the southwest, St. Bernard Parish to the southeast, and Tangipahoa Parish to the west. Live parish/county pages: Washington Parish, Hancock County, Mississippi, Jefferson Parish, and Tangipahoa Parish. Orleans Parish, St. Bernard Parish, and Pearl River County, Mississippi have no live page on this site yet.

Demographics

St. Tammany Parish had 264,570 residents at the 2020 census, the fourth-most populous parish in Louisiana. Slidell (27,655) and Mandeville (11,560) are the two largest communities, followed by the parish seat, Covington (8,655). Median household income runs well above the Louisiana median of $58,229, reflecting the parish’s role as a New Orleans-area commuter suburb. Population density is roughly 313 people per square mile of land.

Economy & Local Life

The parish’s economy centres on suburban commerce, healthcare, and light industry serving the greater New Orleans metro area, with a substantial share of residents commuting across the lake via the Causeway or through I-10 and I-12. Chevron relocated its regional Gulf Coast headquarters to a Covington office park in 2008. Northshore hospital systems, Southeastern Louisiana University’s Slidell-area programs, and a growing craft-brewing and tourism scene around Abita Springs and downtown Covington round out the local economy.

History

St. Tammany Parish was created on October 27, 1810, out of the former Spanish district of West Florida. It is named for Tamanend, a 17th-century Lenape chief renowned for negotiating peace with William Penn’s Pennsylvania colony — making it the only Louisiana parish named for a “saint” who was never canonized by the Catholic Church. The parish’s population has grown roughly fourfold since 1970, with a sharp acceleration after Hurricane Katrina in 2005 as thousands of New Orleans-area residents relocated to the north shore.

Getting There

Interstate 12 runs east-west through the parish, Interstate 10 and Interstate 59 clip its southeastern and northeastern corners, and US 190 and US 90 serve the older town centres. The Lake Pontchartrain Causeway links Mandeville directly to New Orleans across the lake.

• New Orleans — 30 miles south, via the Causeway or I-10/I-610
• Hattiesburg, Mississippi — 70 miles north, via US 11/I-59
• Baton Rouge — 55 miles west, via I-12
• Gulfport, Mississippi — 45 miles east, via I-10/I-59

The nearest major commercial airport is Louis Armstrong New Orleans International Airport, about 40 miles southwest of Covington.

Frequently Asked Questions

Where is St. Tammany Parish?
It is on the north shore of Lake Pontchartrain in southeastern Louisiana, directly across the lake from New Orleans.

What is the population of St. Tammany Parish?
264,570 at the 2020 census, the fourth-highest of Louisiana’s 64 parishes.

How big is St. Tammany Parish?
846 square miles (2,190 km2) of land, plus about 279 square miles of lake and bayou water.

What is the St. Tammany Parish seat?
Covington is the parish seat.

How many towns and cities are in St. Tammany Parish?
Three cities (Slidell, Mandeville, Covington) and three towns (Pearl River, Abita Springs, Madisonville), plus several unincorporated communities.

What ZIP codes are in St. Tammany Parish?
Thirteen delivery ZIP codes, led by 70433 and 70435 (Covington), 70458/70460/70461 (Slidell), and 70448/70471 (Mandeville).

Why is it called St. Tammany?
It is named after Tamanend, a Lenape chief known for peacemaking with early Pennsylvania colonists, not a canonized Catholic saint.

More counties in this state: Towns and villages in Louisiana.