Catherine Liller founded EcoSite Advisors LLC in 2025 after 23 years working for the Federal government in environmental policy, regulation, permitting, and infrastructure planning. Catherine’s expertise in policy and government regulations, combined with her working relationships throughout the transportation industry has afforded her the technical and personal skills required to carry out the integration of landscape-level conservation and infrastructure development. During her time with the Federal Highway Administration (FHWA), Catherine served in the Resource Center, providing technical assistance and training to FHWA Division Offices, State Departments of Transportation, and other local agency partners on transportation planning, permitting, and delivery. In this role, Catherine served as a technical expert on environmental law, policy, regulation, and permitting. During Catherine’s 21 years with the U.S. Fish and Wildlife Service (FWS), she served in the Environmental Contaminants Program, Habitat Conservation Program, and Ecological Services Program at the regional and headquarters office levels. At FWS, Catherine also spent 15 years as the National Transportation Liaison to FHWA, where she worked with transportation partners to identify best practices for streamlining the environmental review process, resolve conflicts, and promote ecologically sustainable transportation infrastructure. In her liaison role, Catherine developed the FWS’ Transportation Community of Practice committed to streamlining regulatory processes, promoting conservation initiatives, and ensuring the timely delivery of linear infrastructure projects. She also led a multi-agency team in the development of an Endangered Species Act programmatic biological opinion on the impact of transportation projects across 42 states on threatened and endangered species. Catherine is a proven leader in interagency collaboration and stakeholder engagement, with skills in impact assessments, technical writing, and training that carries over to clients of EcoSite Advisors and IPaC Associates to further advance infrastructure planning and development through regulatory processes.

Expertise:

• Environmental law, regulations, and policy

• Streamlining regulatory processes and permitting

• Collaboration and stakeholder engagement

• Conflict Resolution

• Technical Training

• Impact Assessment

• Technical Writing

• Mitigation Planning

Leadership:

Management:

• National Federal, state, local, and private partnerships

• Programmatic planning

• Revenue Sources

• Grant development and review

Regulations Including:

• Endangered Species Act

• National Environmental Policy Act

• Clean Water Act

• Migratory Bird Treaty Act

• Infrastructure Investment and Jobs Act and associated FHWA regulations

• Section 4f of the U.S. Department of Transportation Act of 1966

Partnerships:

• U.S. Fish and Wildlife Service

• National Marine Fisheries Service

• U.S. Forest Service

• Bureau of Land Management

• Environmental Protection Agency

• U.S. Army Corps of Engineers

• U.S. Coast Guard

• Natural Resources Conservation Service

• Advisory Council on Historic Preservation

• Federal Highway Administration

• Federal Railroad Administration

• State Departments of Transportation

• Transportation Research Board

• American Association of State Highway and Transportation Officials

• Non-profit conservation organizations

Markets Including:

• Threatened and Endangered species

• Biodiversity and habitat conservation

• Water quality

• Wetlands

• Coastal environments

• Transportation

• Community planning

• Multi-stakeholder infrastructure planning

• Programmatic approaches

• Developing partnerships and facilitating conflict resolution