Sarah Clark:

One of the earliest published references to Cumberland County's first
hanging grounds could be a Nov. 6, 1799, report in The Carlisle
Gazette on the execution of Sarah Clark.

Convicted of poisoning the family of John Carothers of East Pennsboro
Township, the newspaper said her hanging was held "on the commons east
of this town."

http://www.cumberlink.com/localnews/2001/02/news2_25_01.html 

The circumstance which resulted in John Carothers' death and a tragedy
in his family was this: A young girl, named Sarah Clark, living in the
family of John Douglas, contracted a strong attachment for
Mr. Douglas' son, who was at that time paying attention to Miss Ann
Carothers, daughter of John Carothers, who lived near Silver Spring
and was a neighbor of Mr. Douglas.  Sarah Clark, overcome by her
infatuation for young Doug- las, determined to destroy the life of Ann
Carothers and gain the object of her affections. With this aim in
view, she hired as a servant in the house of Mr. Carothers and bided
her time. Having no ill will against the family, she desired to poison
only Ann, and with this in view, she purchased some arsenic. But no
suitable opportunity offering, she grew desperate and put the arsenic
in a pot of leaven.  The family all ate of the bread and became
sick. Captain John Carothers died on the 26th of February, 1798, and
his wife, Mary, died soon afterward. Ann Carothers, the intended
victim, survived. Andrew Carothers, her brother, also survived, but
was a cripple for life. Sally was tried, convicted, and hanged at
Carlisle.

http://www.geocities.com/Heartland/Ranch/7834/rcarruthers1.html