is the cost of creating a family trust deductible

Yes, trust preparation fees are deductible if they are for:  

• the production or collection of income, or
• the management of the property held for production of income, or
• tax advice and tax planning

If your total legal fees include both the above and other fees for non-deductible items (that don't meet the above criteria) you will need to allocate the amount between deductible and non-deductible items.

 

These expenses are part of allowable itemized deductions (so you will need enough itemized deductions to make them count.) 

1. Federal Taxes
2. Deductions & Credits
3. Scroll down to Other Deductions and Credits
4. Select Legal Fees

Not deductible after tax reform