▁land ▁is ▁level ▁and ▁continuous — it ▁is ▁not ▁phys ically ▁pract ic able ▁to ▁range ▁across ▁large ▁de press ions ▁or ▁significant ▁water ways , ▁for ▁example . ▁On ▁s lop ing ▁land , ▁the ▁chain ▁was ▁to ▁be ▁" le ve led " ▁by ▁raising ▁one ▁end ▁as ▁needed , ▁so ▁that ▁und ulations ▁did ▁not ▁increase ▁the ▁apparent ▁length ▁of ▁the ▁side ▁or ▁the ▁area ▁of ▁the ▁tract . ▁ ▁Unit ▁of ▁length ▁ ▁Although ▁G unter ' s ▁chain ▁was ▁later ▁su pers eded ▁by ▁the ▁steel ▁t ape ▁( a ▁form ▁of ▁t ape ▁measure ), ▁its ▁legacy ▁was ▁a ▁new ▁stat ut ory ▁unit ▁of ▁length ▁called ▁the ▁chain , ▁equal ▁to ▁ 6 6 ▁feet ▁( or ▁ 1 0 0 ▁links ). ▁This ▁unit ▁still ▁exists ▁as ▁a ▁location ▁identifier ▁on ▁British ▁rail ways , ▁as ▁well ▁as ▁in ▁some ▁areas ▁of ▁America . ▁In ▁the ▁United ▁States ▁( US ), ▁for ▁example , ▁Public ▁Land s ▁Survey ▁pl ats ▁are ▁published ▁in ▁the ▁chain ▁unit ▁to ▁maintain ▁the ▁consist ency ▁of ▁a ▁two - h undred - year - old ▁database . ▁In ▁the ▁Mid west ▁of ▁the ▁US ▁it ▁is ▁not ▁un common ▁to ▁encounter ▁de eds ▁with ▁references ▁to ▁ch ains , ▁pol es , ▁or ▁rod ▁units , ▁especially ▁in ▁far ming ▁country . ▁Minor ▁roads ▁survey ed ▁in ▁Australia ▁and ▁New ▁Zealand ▁were ▁in ▁the ▁ 1 9 th ▁and ▁early ▁ 2 0 th ▁centuries ▁custom arily ▁one ▁chain