tie

In surveying, a tie is a measured connection from a property corner or boundary point to an external, permanent reference mark. This reference, usually called a benchmark or iron, sits beyond the lot itself, often on a building foundation, utility pole, or driven iron spike. The tie consists of two elements: the bearing (direction) and the distance from the property point to that reference mark. It serves as a way to recover or verify a lot corner's position if original monuments become lost or unclear.

Ties are essential for deed research and boundary retracement. When a surveyor resurveys an old property, original corner monuments may have been removed by construction, erosion, or simply age. A well-documented tie recorded in the original field notes allows the surveyor to relocate that corner with confidence, even decades later. The reference mark must be stable, durable, and unlikely to move; a building corner or established iron is suitable, whereas a tree or fence post is not.

A tie is written in the survey record as a bearing and distance pair, for example: "N 47° 30' E, 156.4 feet to iron in curb." Distance is measured by chain, tape, or electronic means depending on the era and precision required. The bearing is taken by compass or transit. Surveyors often establish multiple ties to the same lot corner for redundancy; if two ties from different references agree, confidence in the corner location is high. If they conflict, the discrepancy signals that either the reference mark has moved or the original measurements were inaccurate.

Ties differ from offsets, which connect nearby line points or structures to the survey line itself, rather than linking a property corner to a remote benchmark. A tie is strictly outbound from the property parcel to something fixed in the wider landscape. This distinction matters for interpreting old surveys and for modern retracement work, where distinguishing what was original control from what was merely a convenience measurement affects reliability.

In practice, ties are particularly common in urban and suburban surveys where multiple permanent structures exist nearby, and in dense historical areas where corner monuments have been lost or built over. Rural surveys may rely more heavily on original monument searches and natural landmarks, though ties to bridges, mills, or church buildings appear frequently in 19th and 20th century field notes. A missing tie, or a tie to a reference mark that has since been destroyed, can make boundary recovery difficult or impossible without resorting to testimony or circumstantial evidence.