Photo of 300 Constitution Ave
Class A Office · General

300 Constitution Ave

Portsmouth, NH 03801

Available spaces

2 for lease · asking rates · updated Oct 7, 2026

Suite 200 at 300 Constitution Ave

Suite 200

$14.00/SF/yr NNN
Size 11,062 SFAvailable Now≈ Monthly $12,906

Class A office spaces are available for lease on the 2nd floor. Suite 1 is an open concept 550± SF single room office. Suite 200 is 11,062± SF consisting of 3 conference rooms, 9 offices, kitchen/break room, IT room, and a large open cube area. Modern designer furniture is included in the lease rate (Suite 200 only). Suites feature high ceilings, lots of windows, and elevator access. Other tenants include X5 Home Loans, Global Laminates, TopMark Funding, Concord Electric, Asian Atlantic Industries, and NERACOOS. Located 3.5± miles to downtown Portsmouth, 2.6± miles to I-95, and 0.6± miles to Route 1.

Suite 1 at 300 Constitution Ave

Suite 1

$903/mo
Size 550 SFAvailable Now

Class A office spaces are available for lease on the 2nd floor. Suite 1 is an open concept 550± SF single room office. Suite 200 is 11,062± SF consisting of 3 conference rooms, 9 offices, kitchen/break room, IT room, and a large open cube area. Modern designer furniture is included in the lease rate (Suite 200 only). Suites feature high ceilings, lots of windows, and elevator access. Other tenants include X5 Home Loans, Global Laminates, TopMark Funding, Concord Electric, Asian Atlantic Industries, and NERACOOS. Located 3.5± miles to downtown Portsmouth, 2.6± miles to I-95, and 0.6± miles to Route 1.

The building

Building
62,322 SF · 3 floors · 2013
Site
5.56 Acres · G1 zoning
Systems
Sprinklered
Occupancy
Single-tenant
Submarket
Apt,PM,0

Comps

Comparable sales and lease data is available to members only.
AW
Andrew Ward · Colliers
Lists 2 of 2 spaces