Bitcoin's block reward halving, occurring roughly every four years, reduces miners' revenue, impacting long-term hashrate distribution. As rewards drop, less efficient miners may exit due to lower profitability, concentrating hashrate among larger, cost-effective operations. This could centralize mining power in regions with cheap energy or advanced hardware. However, increased Bitcoin price post-halving often offsets reduced rewards, incentivizing miners to continue. Historical data shows hashrate growth despite halvings, driven by price surges and technological advancements. Still, geographic and economic factors, like energy costs and regulatory shifts, significantly influence distribution. Centralization risks remain if smaller miners can't compete.