About HDM Law

HDM Law is a solo law practice run by lawyer Heather Marshall out of an office in Thornhill, in York Region just north of Toronto. The practice serves clients in Vaughan, Markham, and Toronto, and focuses on three areas: wills, estates and trusts, real estate, and commercial leasing. Marshall earned a Bachelor of Laws from Osgoode Hall Law School in 2007 and won the Dominic Carinci Memorial Prize for achievement in real estate and business associations while there. Marshall was called to the Bar of Ontario in 2008, after articling at a downtown Toronto firm, and worked at a mid-sized full-service firm in North York and a large downtown firm before opening an independent practice.

The estate planning side of the practice includes training beyond the required minimum. In 2019, Marshall completed the Osgoode Professional Development Intensive Program in Wills and Estates. The leasing practice has a published component too, since Marshall co-authored a chapter in Shopping Centre Leases (2nd Edition), a reference text used in the field. HDM Law describes its approach as personalized, timely, and cost-effective, with advice meant to be practical and understandable rather than dense with jargon. The office relocated in October 2019 to its current location at Yonge and John in Thornhill.

Milestones & recognition

  • Earned a Bachelor of Laws from Osgoode Hall Law School in 2007 and won the Dominic Carinci Memorial Prize for achievement in real estate and business associations.
  • Called to the Bar of Ontario in 2008, after articling at a downtown Toronto firm.
  • Worked at a mid-sized full-service firm in North York and a large downtown firm before opening an independent practice.
  • Co-authored a chapter in Shopping Centre Leases (2nd Edition), a reference text on commercial lease law.
  • Completed the Osgoode Professional Development Intensive Program in Wills and Estates in 2019.
  • Relocated the practice to its current office at Yonge and John in Thornhill in October 2019.

Good to know

A person using a wheelchairWheelchair accessibleA calendar with a checkmark beside a clockBy appointment

The neighbourhood

HDM Law's office sits at the corner of Yonge and John in Thornhill, in York Region just north of Toronto, where the practice relocated in October 2019. The location keeps the office within easy reach of Vaughan, Markham, and Toronto without being anchored to any single one of them, which fits a practice that draws clients from across all three. Clients who drive have free parking directly behind the building, reached from Thornridge Drive.

Frequently asked questions

What areas of law does HDM Law handle?
HDM Law handles wills, estates and trusts, real estate, and commercial leasing from a single office in Thornhill, serving clients in Vaughan, Markham, and Toronto.
Can I get help buying or selling a home in Vaughan or Markham?
HDM Law handles residential purchases, sales, and mortgage or refinance transactions, and reviews new home and condo agreements of purchase and sale for buyers in Vaughan, Markham, and Toronto.
Does HDM Law prepare wills and powers of attorney?
HDM Law prepares wills and powers of attorney for property and personal care, and also handles more complex estate planning involving business ownership, cottage properties, or blended families.
I run a small business and need my commercial lease reviewed before I sign. Can the firm help?
HDM Law drafts, reviews, and negotiates commercial leases for office, retail, and industrial tenants and landlords, working from a client's own form of lease or drafting one from scratch.
Does HDM Law offer a free consultation?
HDM Law offers a complimentary phone consultation for wills and estates matters, and a complimentary 15-minute consultation for commercial leasing questions.
Where is the office located, and is there parking?
HDM Law is located at 7636 Yonge Street in Thornhill, at the intersection of Yonge and John, with free parking available directly behind the building, accessible from Thornridge Drive.

Where to find them

7636 Yonge Street, Thornhill, Ontario L4J 1V9 · 416-800-7349

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Listing compiled from the firm’s public website in September 2026. Verify licence status in the Law Society of Ontario directory ↗