Selling Expensive Lot

Have you consulted a tax lawyer or a CPA about the tax consequences of selling that land?  Unless by some slim chance you can consider it part of your house lot and you are selling your own home quite soon, the homeseller's $500,000 exclusion won't work for you.   And if you hope to consider it investment property and are planning to buy similar "like-kind" property, there are strict requirements about paperwork, deadlines and handling the money that you should investigate before you go any further.  For that one, a SEction 1031 exchange, you wouldn't "avoid" being taxed -- you'd just get a chance to postpone taxes.
By all means get to a professional for advice before you go any further.  My guess is that you will indeed owe capital gains tax on your profit.