Penn Township, Lancaster County, Pennsylvania, population 9,870 (2018), lies five miles north of the City of Lancaster and 60 miles west of Philadelphia. In 2011, the Township adopted a TDR code aimed at preserving prime farmland, sensitive natural areas and rural character. 

Sending areas are located in the T-2 Agricultural District or T-1 Natural District. Minimum lot size to qualify as a sending site is 20 acres in the T-2 and 10 acres in the T-1. TDR allocation is calculated by multiplying the acres in a sending site by 0.5. The ordinance specifically allows parcels owned by government entities to be sending sites. TDRs are severed by recording of a permanent conservation easement approved by the township solicitor and a deed of transferable development rights with a signed endorsement by the township.

TDRs can be used to increase receiving site density in five scenarios.

1. T-4 Cluster Developments can increase from a baseline of one unit per acre to four units per acre at the ratio of one bonus dwelling unit per TDR.  
2. T-4 TND Developments can increase from a baseline of three units per acre to five units per acre at the ratio of one bonus dwelling unit per TDR.  
3. T-5R Cluster Developments can increase from a baseline of three units per acre to five units per acre at the ratio of one bonus dwelling unit per TDR.  
4. T-5 TND Developments can increase from a baseline of six units per acre to eight units per acre at the ratio of one bonus dwelling unit per TDR.  
5. CCRC Developments can increase from a baseline of four units per acre to 12 units per acre at the ratio of two bonus dwelling units or three beds per TDR.  

The ordinance explains that building below baseline density increases the consumption of land and forces the township to rezone land intended for conservation. Consequently, receiving sites can also use TDRs to build below baselines in the following three scenarios.

1. T-5R Cluster Developments can be developed at less than three units per acre when one TDR is retired for each unit below baseline density. 
2. Manor House and Multi-Family Developments can be developed at less than six units per acre when one TDR is retired for each unit below baseline density.
3. TND Developments can be developed at less than six units per acre when one TDR is retired for each unit below baseline density.

Receiving sites in five residential, non-residential and mixed-use zones can increase their building footprint baselines at the ratio of 4,000 square feet per TDR.

Receiving sites in seven zones may exceed lot coverage baselines at the ratio of 4,000 square feet per TDR up to the with-TDR lot coverage maximums stipulated for each zone. TDRs used to exceed building footprint baselines cannot also be used to exceed lot coverage baselines or building height.

Receiving sites in two zones can exceed building height baselines at the ratio of 4,000 square feet of floor area per TDR. With-TDR maximum building height is 60 feet in the CCRC and 70 feet in the D-3 district. 

The ordinance allows the township to buy, hold, sell or extinguish TDRs. The township can also convey TDRs to a conservancy or the Lancaster County Agricultural Preservation Board with the understanding that proceeds from the sale of these TDRs must be used to purchase TDRs in Penn Township.