In 1854, Esther Isherwood or Pilkington (so probably a widow) married Charles Horrocks.
By 1861, Charles was a widower, so Esther must have died. The only Bolton death is for Esther Horrocks of Westhoughton in 1855, aged 30. It appears that this Esther died shortly after giving birth to a daughter (unnamed), that also died. However, this is another Esther Gregory (1825-1855) that married Joseph Horrocks. Another Esther Horrocks died in N Bury in 1859, aged 53, but this Esther seems a little old. There is also Esther that died 1858 in Blackley, near Middleton, aged 42. This is further away, but a better age match for Charles.