The maiden measured, indicated and inferred resource for the Kathleen's Corner and Mt Mann deposits is 21.2 million tonnes at 1.4% lithium oxide and 170 parts per million tantalum pentoxide, using a 0.5% lithium oxide cut-off.
Three quarters of the resource is in the measured or indicated categories.
Liontown managing director David Richards said the company was pleased with the first number.
"It came out bigger than we thought it would when we first acquired the project 18 months ago," he told MNN.
Richards said the 1.4% lithium oxide grade was pleasing and the project had good tantalum credits.
In addition, the resource sits on a granted mining lease and is close to existing roads and other infrastructure.
"It's got a lot going for it," Richards said.
Lithium mineralisation starts from surface and hosted by spodumene-bearing pegmatites.
The resource remains open along strike and at depth with drilling to continue with the aim of growing the inventory.
Metallurgical testwork is underway, which will feed into a scoping study.
"We should have results by the end of this month," Richards said.
The company is looking to recruit a dedicated project manager ahead of a possible feasibility study next year.
Liontown is well-funded with A$3 million cash.
The company was approached by potential customers from China, Korea and Chile at the start of the year, but wanted to wait until a maiden resource to talk.
Richards said Liontown would now follow up these approaches.
Despite some pullback in lithium in recent months, Richards said there was still a lot of interest and the drop in sentiment was only short-term.
"We're reasonably confident if we stick to our guns, it will all work out," he said.
The company also holds the Buldania lithium project outside Norseman where a maiden resource is the aim.
Assays for the second drilling program are currently pending.
Liontown shares opened 6.3% higher at 3.4c.