▁in ▁the ▁soil . ▁They ▁are ▁especially ▁abund ant ▁in ▁the ▁West ▁of ▁Ireland , ▁particularly ▁Con nem ara . ▁They ▁may ▁also ▁be ▁found ▁throughout ▁the ▁Mediter rane an , ▁including ▁retain ing ▁walls ▁used ▁for ▁ter rac ing . ▁Such ▁constru ctions ▁are ▁common ▁where ▁large ▁stones ▁are ▁pl ent iful ▁( for ▁example , ▁in ▁The ▁B urr en ) ▁or ▁conditions ▁are ▁too ▁har sh ▁for ▁h ed ges ▁capable ▁of ▁retain ing ▁liv est ock ▁to ▁be ▁grown ▁as ▁reliable ▁field ▁boundaries . ▁Many ▁thousands ▁of ▁miles ▁of ▁such ▁walls ▁exist , ▁most ▁of ▁them ▁centuries ▁old . ▁ ▁In ▁the ▁United ▁States ▁they ▁are ▁common ▁in ▁areas ▁with ▁rock y ▁so ils , ▁such ▁as ▁New ▁England , ▁New ▁York , ▁New ▁Jersey , ▁and ▁Pennsylvania , ▁and ▁are ▁a ▁notable ▁characteristic ▁of ▁the ▁bl u egr ass ▁region ▁of ▁central ▁Kentucky ▁as ▁well ▁as ▁Virginia , ▁where ▁they ▁are ▁usually ▁referred ▁to ▁as ▁rock ▁f ences ▁or ▁stone ▁f ences , ▁and ▁the ▁Nap a ▁Valley ▁in ▁north ▁central ▁California . ▁The ▁technique ▁of ▁construction ▁was ▁brought ▁to ▁America ▁primarily ▁by ▁English ▁and ▁Sc ots - I r ish ▁imm igr ants . ▁The ▁technique ▁was ▁also ▁taken ▁to ▁Australia ▁( pr inci p ally ▁western ▁Victoria ▁and ▁some ▁parts ▁of ▁Tas mania ▁and ▁New ▁South ▁Wales ) ▁and ▁New ▁Zealand ▁( es pecially ▁O tag o ). ▁ ▁Similar ▁walls ▁also ▁are ▁found ▁in ▁the ▁Swiss – Ital ian ▁border ▁region , ▁where ▁they ▁are