F–S–T sequences

A very sharp eye might notice that Pittsburgh has several sets of usually parallel streets beginning with letters in the sequence F, S, T, F, F, S, S, E, N, T, . . . (occasionally obscured by having a few different letters). These sequences often arise from their origins as numbered streets. The city of Pittsburgh grew by absorbing other towns and villages, and it was common that these towns had a sequence of streets named First, Second, Third, and so forth. After these areas were annexed into the city, the names of the streets were changed to avoid duplication with Pittsburgh's numbered street sequence up the Allegheny River. But usually the first letter of the street name was preserved, which led to the modern F–S–T sequences.

East Allegheny

Original name	Changed to
First Street	Foreland Street
Second Street	Suismon Street
Third Street	Tripoli Street

Esplen

Original name	Changed to
First Street	Fernwood Street (now Stanhope Street)
Second Street	Sagamore Street
Third Street	Tabor Street
Fourth Street	Florien Street
Fifth Street	Frustum Street
Sixth Street	Saginaw Street
Seventh Street	Sanford Street
Eighth Street	Earl Street
Ninth Street	Navarre Street
Tenth Street	Telford Street
Eleventh Street	Edgecliffe Street

Sheraden

Original name	Changed to
First Street	Faust Street
Second Street	Swatsworth Street (now Stanhope Street)
Third Street	Tweed Street
Fourth Street	Faulkner Street
Fifth Street	Fairdale Street
Sixth Street	Sutherland Street
Seventh Street	[Aschenez Street (now Adon Street)]
Eighth Street	Emporia Street
Ninth Street	Newcomer Street
Tenth Street	Turbett Street (now Tybee Street)
Eleventh Street	Eliska Street
Twelfth Street	Tuxedo Street
Thirteenth Street	Thayer Street
Fourteenth Street	Fadette Street
Fifteenth Street	Faronia Street
Sixteenth Street	[Middletown Road]

Original name	Changed to
First Avenue	Fusion Street
Second Avenue	Swentzell Street (now part of Berry Street)
Third Avenue	Toledo Street
Fourth Avenue	Frontenac Street